Post on 24-Mar-2020
Drinking Water Quality
Annual Report 2012/13
2 Title 2 Drinking Water Quality Annual Report 2012/13
Contents
Common terms .............................................................. 2
Summary ....................................................................... 5
Our commitment to you ................................................. 6
Introduction .................................................................. 7
Where does your water come from? .............................. 8
Perth Metropolitan Region.................................................. 8
South West Region ......................................................... 11
Goldfields and Agricultural Region..................................... 12
Great Southern Region .................................................... 13
North West Region .......................................................... 14
Mid West Region............................................................. 15
What drinking water guidelines must we meet? .......... 16
Case Studies ................................................................ 22
Case Study 1: Introduction to the Framework for
Management of Drinking Water Quality ............................. 22
Case Study 2: Source Protection Signage and
Barrier Project ............................................................... 24
Case Study 3: Feed Forward Control ................................. 25
How is your water treated? ......................................... 27
Understanding water quality test results .................... 31
Performance at a glance .............................................. 36
Customer expectations ................................................ 39
Improving your water quality ..................................... 41
Appendix A – List of parameters within sampling
groups ......................................................................... 43
Appendix B – List of all sampling parameters ............. 46
Appendix C – Summary of test results ......................... 48
Appendix D - Supporting information for water source
location maps .............................................................. 49
ISSN 2202-879X October 2013
3 Title 3 Drinking Water Quality Annual Report 2012/13
About this report
The Water Corporation’s 2012/13 Drinking Water Quality
Annual Report is a review of our performance for the financial
year ending 30 June 2013.
This report is specifically designed to provide our customers
and the Western Australian public with information on the
quality of their drinking water.
Publication of this report allows us to meet the requirements of
the Australian Drinking Water Guidelines, our Operating
Licence requirements with the Economic Regulation Authority,
the requirements of the Memorandum of Understanding with
the Department of Health and the reporting requirements of
the National Water Commission.
4 Title 4 Drinking Water Quality Annual Report 2012/13
ADWG Australian Drinking Water Guidelines
CAWS Country Areas Water Supply
DOC Dissolved organic carbon
DPaW Department of Parks and Wildlife
DoW Department of Water
EDR Electrodialysis Reversal
GAWS Goldfields and Agricultural Water Supply
GSTWS Great Southern Towns Water Supply
IWSS Perth Integrated Water Supply Scheme
LGSTWS Lower Great Southern Towns Water Supply
LTE Long Term Evaluation
MIEX Magnetic Ion Exchange
ML One megalitre (equals one million litres)
MWSSD Metropolitan Water Supply, Sewerage and Drainage
NHMRC National Health and Medical Research Council
PDWSA Public Drinking Water Source Area
RO Reverse Osmosis
UV Ultra-violet Disinfection
WSAA Water Services Association of Australia
WSP Water Safety Plan
Common terms
5 Title 5 Drinking Water Quality Annual Report 2012/13
Supplying safe drinking water is our highest priority. In
2012/13, we achieved outstanding compliance results for
health-related characteristics and met all our health targets for
drinking water quality set by the Department of Health.
Health related performance:
100 per cent compliance with microbiological guidelines
100 per cent compliance with health related chemical
guidelines
Non-health (aesthetic) related performance:
64 per cent compliance with aesthetic guidelines
We strive to meet guidelines for aesthetic characteristics,
however, this is very difficult to achieve in a state as vast as
Western Australia with a wide variety of water sources. This is
especially the case in some of our small country water
schemes where there can be few sources of water drinking
available and where installation of treatment can be very
costly.
Although we meet all our obligations under the Operating
Licence, we recognise there are always opportunities for
improvement.
This is our 11th Drinking Water Quality Annual Report and we
trust this report provides our customers with the information
they require about their drinking water quality. We welcome
any comments and feedback by contacting us on 13 13 75 or
report@watercorporation.com.au
Summary
Two Peoples Bay, Great Southern Region
6 Title 6 Drinking Water Quality Annual Report 2012/13
We are committed to providing our customers with safe, high-
quality supply drinking water that consistently meets the
Australian Drinking Water Guidelines (ADWG), customers and
other regulatory requirements.
To achieve this, we will in partnership with stakeholders and
relevant agencies:
Take a ‘catchment to tap’ approach to managing and
protecting water quality from the source through to our
customers.
Strongly advocate source protection and primacy of
drinking water quality over other land uses.
Use a risk-based approach to identify and manage
potential threats to water quality.
Comply with the health-related criteria of the ADWG
and work to progressively improve compliance with
aesthetic criteria.
Use appropriate contingency planning and incident
response capability.
Incorporate the needs and expectations of our
customers, stakeholders, regulators and employees.
Routinely monitor the quality of drinking water and use
effective reporting mechanisms to provide relevant and
timely information, and promote confidence in the
water supply and its management.
Participate in research and development activities to
ensure continued understanding of drinking water
quality issues and performance.
Contribute to setting industry regulations and
guidelines, and other standards relevant to public
health and the water cycle.
Continually improve our practices by assessing
performance against corporate commitments and
stakeholder expectations.
We will implement and maintain a management system
consistent with the ADWG to protect our drinking water
quality. All managers and employees involved in the supply of
drinking water are responsible for understanding,
implementing, maintaining and continuously improving the
drinking water quality management system.
Our commitment to you
7 Title 7 Drinking Water Quality Annual Report 2012/13
We provide drinking water to Perth and over 220 small
communities scattered throughout Western Australia.
This year we delivered 357.3 billion litres of drinking water
from 126 dams and weirs, 94 licensed borefields and the Perth
and Southern Seawater Desalination plants, to over a million
properties through 33,823 kilometres of water mains.
To put that into perspective, that means that last year we
supplied enough water to fill Pattersons Stadium to its
goalposts nearly 358 times.
Under our Operating Licence we comply with a Memorandum
of Understanding with the Department of Health. We act in
accordance with the microbiological, health chemical and
radiological parameters as specified by the National Health and
Medical Research Council (NHMRC) in the ADWG.
Our health performance (chemical, microbiological, and
radiological) has this year again resulted in 100 per cent of
metropolitan and country localities meeting the high standards
set by the Department of Health.
An extensive drinking water quality monitoring program
confirms the safety of the water we provide to our customers.
Bacterial and chemical analyses are carried out by
independent laboratories, approved by the Department of
Health.
Victoria Dam
Introduction
8 Title 8 Drinking Water Quality Annual Report 2012/13
This section provides an overview of the water supplies in each
of our six regions.
Perth Metropolitan Region
Our largest scheme, the Integrated Water Supply Scheme
(IWSS) delivers 285 billion litres of water each year to more
than 1.9 million customers in Perth, the Goldfields and
Agricultural Region, and parts of the South West.
Surface water comes from eight dams in the Darling Range:
South and North Dandalup, Serpentine, Wungong, Churchman
Brook, Canning, Victoria and Mundaring Weir. Water is also
supplied from Stirling and Samson Dams in our South West
Region.
Groundwater is drawn from the Yarragadee, Leederville,
Mirrabooka and other shallow aquifers. Most of the 180 bores
are located in Perth's northern suburbs. Groundwater is
treated at six groundwater treatment plants. There are also 12
independent artesian bores which pump water directly into
service reservoirs.
In 2012/13, drinking water production for the IWSS was
delivered on target and within overall water allocation and
license parameters. Total groundwater abstracted was 140.2
billion litres, against an allocation of 140.3 billion litres. Water
supplied consisted of 33 per cent surface water, 40 per cent
Where does your water come from?
9 Drinking Water Quality Annual Report 2012/13
Diagrammatic representation of the main Drinking Water sources for Perth (from Water Corporation's How water gets to my tap Lesson Plan
groundwater and 27 per cent from desalination. The
proportion of desalinated water will increase to above 40 per
cent when the second stage of the Southern Seawater
Desalination Plant is fully commissioned in late 2013.
To optimise the amount of water available for the IWSS,
customers may receive a mix of groundwater, surface water
and desalinated seawater. The percentage of each depends on
seasonal factors. Yanchep and Two Rocks are special cases in
the Perth region, as they have their own independent
groundwater supplies. Eventually these suburbs will join the
IWSS.
The Perth Seawater
Desalination Plant in
Kwinana exceeded its
rated annual production
capacity of 45 billion litres
by delivering 48.3 billion
litres into the IWSS. This
is the fourth year in a row
this climate independent
source has achieved above
average production. This is
the result of ongoing
improvements and
efficiency measures at the
plant. The desalinated water enters the IWSS through
Thomsons Reservoir where it is blended with Jandakot
groundwater and surface water from dams. A portion can be
stored in Canning Dam and Wungong Dam during periods of
low demand in the winter.
The Southern Seawater Desalination Plant in Binningup, which
last year won Desalination Plant of the Year at the Global
Water Awards, continued to increase production, delivering
47.4 billion litres for the 2012/13 year. In response to our
drying climate the decision was made to double the capacity of
the plant to 100 billion litres of water per year.
Southern Seawater Desalination, Binningup
10 Drinking Water Quality Annual Report 2012/13
Together, these two climate independent water sources will be
able to provide above 40 per cent of drinking water to the
IWSS.
The Mundaring Water Treatment Plant and pump station is
being commissioned with first water due from the plant due
into the system at the end of 2013. Launched in 2011, this
work is being funded, built and operated by Helena Water
consortium (compromising ACCIONA Agua, TRILITY and Lloyds
Bank Corporate Markets), in Western Australia’s first Public
Private Partnership (PPP) in the water industry. Helena Water
will provide us with drinking water to meet the needs of the
Goldfields and Agricultural Water Supply (GAWS) for up to 35
years, when the plant will be handed over to us in full
operating condition. We are combining private sector
commerciality with our technical expertise, to drive efficient
operations and lowest possible cost. The Aroona Alliance
manages our metropolitan water production and the Perth
Region Alliance has responsibility for the operations and
maintenance of all our metropolitan services.
Mundaring Weir Wall
11 Drinking Water Quality Annual Report 2012/13
South West Region
Towns in the South West Region are supplied with water from
a number of surface and groundwater sources that are largely
independent. Harvey, Waroona, Hamel, Binningup, Myalup and
Yarloop are supplied from the IWSS.
Bridgetown, Nannup, Hester, Boyup Brook, Greenbushes,
Balingup and Manjimup are now connected to the Warren
Blackwood Regional Water Scheme and can be supplied from a
Yarragadee Bore near Nannup via the Millstream and
Manjimup Dams. In December 2012, we completed an
upgrade to Millstream Dam near Bridgetown, which is central
storage for the Warren-Blackwood Regional Water Supply
Scheme. The upgrade doubled the dam’s capacity to 1.06
billion litres.
Australind, Eaton, Pelican Point, Millbridge, Treendale,
Kingston, Brunswick Junction, Roelands and Burekup are
supplied with water sources from Leederville and Yarragadee
bores, via water treatment plants in Australind, Eaton and
Picton. Harris Dam supplies Collie, Allanson and Darkan as well
around 35 towns in the Great Southern Region.
The Margaret River was used for the last time in 2012/13 to
ensure the Ten Mile Brook Dam had adequate storage for the
summer 2012/13. The pump back is no longer required due to
12 Drinking Water Quality Annual Report 2012/13
commissioning of the Lilly Road Water Treatment Plant and
the Margaret River Production Bore 1/10.
Some of our customers in Australind experienced discoloured
water in 2012/13. Discoloured water is caused by an increase
in flow or change in direction of water, which can stir up
harmless sediment that has settled in pipes over a long period
of time. We conducted an extensive pipe and tank cleaning
program to alleviate the issue.
We review similar schemes across the state and initiate
cleaning programs as required to reduce the chance of
discoloured water for our customers.
Goldfields and Agricultural Region
The Goldfields and Agricultural Water Supply (GAWS) draws
most of its water from Mundaring Weir near Perth and supplies
the majority of towns in the Goldfields and Agricultural Region.
The remaining towns, Laverton, Leonora, Menzies and Wiluna
are supplied from local groundwater sources.
Water supplied to most of the towns is chloraminated with the
remainder being chlorinated (refer to “Disinfection” on page
27). In Kalgoorlie-Boulder, a recently commissioned separate
inlet system to Mt Percy and Mt Charlotte tanks enables all of
the supply to be delivered via tanks, resulting in a more
13 Drinking Water Quality Annual Report 2012/13
consistent amount of chlorine in the water being supplied to all
customers.
Work is due to start on the construction of the Cunderdin
storage tanks which will replace the old unroofed Cunderdin
Reservoir.
Great Southern Region
In the Great Southern Region, we have two main water supply
schemes - the Great Southern Towns Water Supply Scheme
(GSTWS) and the Lower Great Southern Towns Water Supply
Scheme (LGSTWS). Harris Dam near Collie is the main source
for the GSTWS and the South Coast borefields are the main
source for the LGSTWS, although a number of towns have
local sources which can contribute to the supply if required.
The area known as the South Coastal District recently joined
our Great Southern Region from the Goldfields and Agricultural
Region. This includes the Condingup, Gibson, Esperance and
Hopetoun groundwater schemes and Grass Patch, Salmon
Gums, Munglinup and Ravensthorpe surface water schemes.
Ravensthorpe has both ground and surface water components
to the scheme.
As part of the long term plan to reduce draw from less suitable
bores, we drilled two additional production bores in Esperance
14 Drinking Water Quality Annual Report 2012/13
this year. In addition, a number of monitoring bores were
drilled in Albany to improve monitoring of groundwater.
We began a source protection initiative in the region last year
and have completed a number of projects. We upgraded
fences and gates at Two People’s Bay, Jerramungup, Narrogin
(Bottle Creek) and Ongerup. We will continue these upgrades
to protect our water sources.
North West Region
The West Pilbara Water Supply Scheme supplies customers in
Karratha, Dampier and the neighbouring towns of Roebourne,
Wickham, Point Samson, Cape Lambert and the Burrup
Peninsula. The scheme currently has two sources: Harding
Dam and Millstream borefield. Rio Tinto Iron Ore is developing
a groundwater source in the Bungaroo Valley, which will free
up water for the scheme.
The East Pilbara Water Supply Scheme supplies customers in
Port Hedland, South Hedland, Wedgefield Industrial Area and
the local port operations. The scheme is supplied with
groundwater from the Yule and De Grey River borefields.
In the Kimberley area, the town of Kununurra is supplied by a
local groundwater source. The remaining towns in the North
West Region are supplied by local independent groundwater
sources, with the exception of Wyndham which is supplied by
Moochalabra Dam.
Additional water sources are coming online with the expansion
of the Cane River borefield in Onslow due to be complete by
the end of 2013. The Yule and De Grey River borefield
15 Drinking Water Quality Annual Report 2012/13
expansion to supply the Hedland scheme will be complete by
2014. Discussions are continuing with Chevron, who are
working with the Water Corporation on new water sources for
Onslow.
Projects driven by sustained growth in the Kimberley Region
are underway to upgrade water supply schemes and
infrastructure. In Broome, work has been completed on a
second storage tank increasing storage capacity by 40 per
cent and a pH correction dosing plant has been installed.
Mid West Region
The Mid West Region, which supplies drinking water to 52
localities, uses independent groundwater sources. In a region
facing challenges from scarce and brackish (highly saline)
water supplies, we are working to ensure reliable access to a
quality drinking water supply.
Over the past 10 months, extensive work has been completed
in the coastal towns (Horrocks, Yerecoin, Seabird, Woodridge,
Moora, Dandaragan and Bindoon) on refurbishing filters within
the water treatment plants in order to improve aesthetic water
quality through the removal of dissolved metals, specifically
iron and manganese.
We also appointed the region’s first Catchment Ranger in
September 2012, a role which reinforces drinking water quality
management processes and water source protection across
the vast Mid West Region.
16 Title 16 Drinking Water Quality Annual Report 2012/13
The National Health and Medical Research Council (NHMRC)
define the requirements for safe drinking water in Australia
through the ADWG. These guidelines include a Framework for
best practice management of drinking water supplies designed
to integrate all facets of the drinking water quality
management and assurance system. We, along with the
Department of Health, contribute to the rolling revision of the
ADWG.
We have a Memorandum of Understanding with the
Department of Health which requires our compliance with the
microbiological, health chemical and radiological parameters
as specified in the ADWG. This forms part of our Operating
Licence as issued by the Economic Regulation Authority. We,
along with the Department of Health, recognise that the
practices and processes used to establish and maintain high
levels of drinking water quality need to be open and
transparent to the community.
A key enhancement of the 2011 ADWG has been the
strengthening of operational monitoring. This means moving
away from just meeting drinking water quality guideline
values, towards a total system management, understanding
risks and continuous improvement. In addition to this, there is
now the requirement of undertaking a Long Term Evaluation
(LTE) when there is a microbiological detection, chemical or
radiological result above the ADWG health guideline. LTE is
used to evaluate whether the system is sufficiently robust to
deliver safe drinking water under all foreseeable conditions.
For aesthetic parameters, the Memorandum of Understanding
states that we should comply as far as practical with the
ADWG for non-health related characteristics. It is accepted
that the achievement of this may take a number of years
bearing in mind the high levels of public expenditure which
would be required to achieve full compliance. For more
information on our program of water quality improvements
please refer to “Improving Your Water Quality” on page 41.
Drinking Water Quality Team, Perth Seawater Desalination Plant
What drinking water guidelines
must we meet?
17 Drinking Water Quality Annual Report 2012/13
Reservoir Protection sign, Mundaring Weir
Multiple barrier approach
Preventing contamination and minimising potential hazards is
an essential part of providing our customers with safe drinking
water. The ADWG emphasise the importance of using multiple
barriers to ensure the safety of drinking water. Barriers
include:
Protected catchments and groundwater recharge areas
Large reservoirs with long water detention (storage)
times
Water treatment (refer to “How is your water treated?”
on page 26)
Disinfection of water
Maintaining chlorine residuals through the distribution
system
Ensuring tanks and bores are sealed to prevent
contamination.
We have been working over an extended period of time to
implement the multiple barrier approach throughout our
drinking water systems.
Water Safety Plans
The development of Water Safety Plans is a process we use to
meet the Department of Health requirement to implement the
Framework for Management of Drinking Water Quality. Water
Safety Plans use a systematic risk management approach from
catchment to tap assessing the risks to each water supply,
ensuring that appropriate preventative measures are in place,
and identifying the operational controls necessary to
consistently ensure the safety of drinking water. Last year’s
report celebrated the completion of all Water Safety Plans
across the state and this year an in-depth review of 41
schemes in the country and 13 in the metropolitan region have
been completed. All Water Safety Plans are continually
reviewed every four years, to re-evaluate the scheme and
update any site or treatment details.
Source Protection
Protection and management of drinking water catchments is
the most important barrier to drinking water contamination as
it ensures the highest quality raw water is used for drinking
water. The ADWG recognises that “prevention of
contamination provides
greater surety than removal
of contaminants by
treatment, so the most
effective barrier is
protection of source water
to the maximum degree
practical”.
Western Australia’s water
regulator, Department of
Water (DoW), has statutory
responsibility for water
18 Drinking Water Quality Annual Report 2012/13
Canning Reservoir - Erosion control
matting to reduce gullying
source protection in Western Australia. Groundwater and
surface water Public Drinking Water Source Areas (PDWSAs)
are proclaimed, gazetted and protected under the Metropolitan
Water Supply, Sewerage and Drainage (MWSSD) Act 1909 or
the Country Areas Water Supply (CAWS) Act 1947 and their
associated by-laws. These by-laws outline activities that
cannot occur in drinking water catchments because they have
the potential to contaminate drinking water supplies.
As of January 2013 the Water Corporation was delegated
catchment management powers from the DoW for all drinking
water sources proclaimed under the CAWS Act 1947. Until this
time, delegated powers only applied to specific delegated
sources in country areas and all metro sources proclaimed
under MWSSD. Among other things, this gives us the power to
prosecute for by-law infringements. You can obtain more
information on Proclaimed public drinking water source areas
through the DoW website www.water.wa.gov.au.
As a delegated source protection authority, we work closely
with the DoW to develop State-wide source protection policies,
guidelines and standards. We have an Operational Agreement
with the DoW which delegates on-the-ground management of
many catchments to us. We have documented procedures and
manuals to guide catchment operations and ensure compliance
with our delegated responsibilities.
Catchment Management
Strategies have been
developed for every
drinking water source to
identify, assess, manage
and minimise adverse
impacts on water quality
which may result from
land uses and other
activities within the
catchment. Each
Catchment Management Strategy includes a risk assessment
of the land uses and catchment activities. Potential risks to
drinking water quality are identified and the assessment is
used to determine the many management options, water
sampling and catchment surveillance programs.
Regular catchment surveillance ensures we are aware of
activities and changes in our catchments. It also provides an
opportunity to educate members of the public that are
performing activities that could contaminate drinking water.
Other responsibilities include feral animal control, weed
control, fencing and sign inspections, rubbish removal, event-
based water sampling, assisting with research, recreation
event inspections, mining and forestry operation inspections
and pollution response.
19 Drinking Water Quality Annual Report 2012/13
These actions protect the natural purification processes in our
dams and aquifers and reduce the risk of contamination of our
raw water sources. In this way, our source protection program
also works towards corporate sustainability goals, minimising
the need for water treatment plants at our sources.
We carry out extensive catchment protection to minimise the
possibility of water sources being contaminated with
pathogens, particularly those carried by humans and domestic
animals such as cows and dogs. These microorganisms can be
carried and transferred into our drinking water sources by
direct body contact with the water, run-off over land when it
rains or dust blown in on the wind. Activities in or close to the
reservoir and feeder streams pose the greatest risk.
To provide extra protection around our catchments where it is
needed the most, DoW legislation includes provisions for
special exclusion zones, detailed below:
• 2 kilometre exclusion areas around the high water
mark of reservoirs known as ‘Reservoir Protection
Zones’
• ‘Wellhead Protection Zones’ of either 300 metres or 500
metres around drinking water production bores.
In the outer catchment areas, the risk of pathogen
contamination is minimised by restricting access to only
passive recreational activities such as hiking and mountain-
biking on designated trails.
20 Drinking Water Quality Annual Report 2012/13
Water Corporation staff collecting a sample
Monitoring
In accordance with the
ADWG, we run an extensive
drinking water quality
monitoring program to
confirm the safety of the
water we provide to our
customers. We take more
than 65,000 water samples
each year from water
sources, treatment plants
and pipe networks which
supply our customers, and
have in excess of 275,000
individual analyses
performed by our
contracted analytical laboratories.
All our water quality monitoring and reporting is coordinated
through our Water Quality Management System. This software
provides many aspects of water quality management and acts
as the central database for all information on drinking water
quality including sampling program design, sampling analysis,
monitoring and reporting. The Water Quality Management
System also automatically issues alerts for results outside
guideline and operational limits and prompts remedial action.
Engagement with Department of Health
Department of Health is the regulator of drinking water quality
in Western Australia. In November 2007, we entered into our
third Memorandum of Understanding with the Department of
Health for managing drinking water quality, our area of
control. The Memorandum of Understanding connects all
facets of nationally and internationally recognised drinking
water guidelines, standards, and quality management
assurance systems. It requires us to notify the Department of
Health within 24-hours when any sample exceeds a set health
value or where any other event could pose a risk to public
health. The Department of Health reviews our monitoring
results and corrective actions. The current Memorandum of
Understanding
provides for the
Department of
Health to conduct a
performance review
of our systems and
databases used to
manage and report
drinking water
quality. In
consultation with the
Economic Regulation
Authority, the
Department of Department of Health, Department of Water
and Water Corporation at Victoria Dam
21 Drinking Water Quality Annual Report 2012/13
Health commissions audits to cover a three year period in line
with our Operating Licence audit. For more information on the
latest audit, please visit the Drinking water quality section of
our webpage www.watercorporation.com.au.
Incident response
We are committed to protecting our water sources and while
every effort is made to prevent water quality incidents from
happening, there will inevitably be times when issues may
occur. We have incident management plans and procedures to
manage any issues with the minimum possible impact on
water quality and our customers.
Gascoyne River floods, December 2010
22 Title 22 Drinking Water Quality Annual Report 2012/13
We have three case studies which illustrate some of the
initiatives we have undertaken to improve drinking water
quality.
Case Study 1: Introduction to the Framework for
Management of Drinking Water Quality
Summary
The 2004 version of the ADWG endorsed a Framework for
Management of Drinking Water recommending a
comprehensive and systematic suite of day-to-day
management practices to ensure the supply of safe drinking
water to our customers. Since then we have implemented the
Framework as a basis for our Drinking Water Quality process
planning and management, as well as the driver of strategy to
reach our desired state.
This best practice Framework aims to assure drinking water
quality and protect public health through a risk prevention
approach encompassing all steps in water production and
supply from catchment to tap. It incorporates the appropriate
elements of the ISO 9001 Quality Management Standard, the
AS/NZS 4360:2004 Risk Management Standard and the
HACCP (Hazard Analysis Critical Control Point) system adopted
internationally by the food industry. The Framework applies
and tailors the key elements of these systems specifically to
the supply of drinking water.
Framework for Management of Drinking Water Quality
The 12 elements of this comprehensive Framework are shown
below.
Case Studies
23 Drinking Water Quality Annual Report 2012/13
Audit (Internal)
In response to the Framework’s formalisation in the ADWG an
internal auditing tool, AQUALITY, was designed by the
Australian water industry and produced by the Water Services
Association of Australia (WSAA). The tool is based on 196 sub-
element questions around the 12 elements in the Framework
and acts as a self-assessment for water utilities, allowing a
rating out of 100 for each element. The tool is a highly
valuable aid to our business of providing safe water to our
customers. The incorporation of the Framework within the
Drinking Water Quality Branch is also internally audited
through our Management Review and Audit Branch.
Audit (External)
The Water Corporation is externally audited every three
years by the Department of Health. Additionally, as part of
our Asset Management Branch’s external Aquamark audit in
2012, the International Water Association (IWA) and WSAA,
rated a key part of our Framework, the Water Quality
Management System, at 98 per cent. This was then written
up as an IWA/WSAA Leading Practice Case Study in the
WSAA Leading Practices Compendium.
Highlights
The Water Corporation uses AQUALITY continuously to assess
Framework implementation progress. A number of elements
have been assessed as “industry best practice” with key
examples given below.
24 Drinking Water Quality Annual Report 2012/13
Case Study 2: Source Protection Signage and
Barrier Project
Challenge
As a result of an internal audit of ‘Drinking Water Source
Protection Management’, we upgraded and increased source
protection barriers in country regions (including fences, gates
and signage) to meet the requirements of our Source
Protection Operations Manual (SPOM).
A number of regional drinking water catchments had
inappropriate, damaged or no signage to
• Mark the catchment boundary or prohibited zones
• Educate people on their presence within a catchment
• Inform the public of by-laws that apply, restricting
certain activities with the potential to contaminate the
water supply
• Inform the public where they can do certain activities
• Provide information on who to call in an emergency at
the site
Solution
In 2012/13 funding was made available under the Water
Quality Capital Improvement Program to:
• Purchase and install about 500 drinking water source
protection signs across the state.
• Manufacture and install swinging boom gates and
associated safety signs to prevent unauthorised access
to South West Region catchments by off-road vehicles.
• Upgrade security fencing and gates at high priority
sources in the Great Southern Region, including: - Two
People’s Bay (Albany), Jerramungup, Bottle Creek
(Narrogin), Gnowangerup, Ongerup and Pinwernying
Dam (Katanning).
Results
The majority of drinking water source protection signs have
been installed and those that remain, in the Mid West Region,
are generally in more remote locations and will be installed as
part of routine work over the next year.
Signage at Mount Magnet
25 Drinking Water Quality Annual Report 2012/13
The program of works to install swinging boom gates at our
catchments in the South West Region was completed in
September 2013. The Department of Parks and Wildlife
(DPaW) (formerly Department of Environment and
Conservation, DEC) approved the installation of all the
proposed gates in South West Region and understood their
value to protect the water supply.
Way forward
In addition to these barrier installations, there will be on-going
work to digitally record the location, condition and details of
these barriers across the state and integrate the information
into our corporate database. Regular inspections of the signs
will occur to check whether the signs are still legible to the
public.
Case Study 3: Feed Forward Control
Challenge
Over the past decade optimising the way in which our
treatment plants respond to changing water source quality has
been an ongoing challenge. Although the use of portable and
online sensor based global technologies has not advanced
significantly during this time, recent advances have been
made in the way in which we utilise this data. As a result, this
project aimed to increase control of our treatment plant to
maximise performance, minimise the use of treatment
chemicals and reduce operating costs, complementing our
“Reduce Reuse Recycle” key management priority.
Solution
An innovative movement towards using feed back control
loops has shown a revolutionary step forward in the way in
which we could operate treatment plants. This has meant, for
the first time, treatment operators can manage treatment
process conditions from a proactive rather than theoretical
reactive approach. This technology is based on integrating
portable online UV/Vis sensor technology (S::CAN) with
predictive coagulant demand software, controlling the
coagulation dose in a proactive (feed forward) way.
Picture of S::CAN Unit at Harding Treatment Plant
26 Drinking Water Quality Annual Report 2012/13
Results
In March 2010, the Mirrabooka Ground Water Treatment Plant
was selected as the test site to trial Feed Forward Control
capacity for advanced natural organic matter and dissolved
metals (Iron and Manganese) removal. In parallel with the
Water Quality Research Australia Project 1020, “Use of on-line
Surrogate Parameters for Rapid Hazard Detection and
Improved System Performance”, process performance for the
removal of natural organic matter (precursors of disinfection
by-products) was assessed.
Outcomes from this work were so successful that Feed
Forward Control was instated as a permanent operational and
process tool. A partial cost benefit analysis was performed
where initial cost impacts, covering the first 15 months of
operation under Feed Forward Control, showed significant cost
reduction per million litres (Chart 1). Furthermore, the
concentration of disinfection by-products in the reticulation
system were about 10 per cent lower, regardless of sample
point.
Way forward
After the successful trial and implementation of the system at
Mirrabooka Ground Water Treatment Plant, we have begun
Stage 2 of a trial at Harding Dam Water Treatment Plant.
27 Title 27 Drinking Water Quality Annual Report 2012/13
Water treatment plants
The specific water quality of each source dictates the type of
treatment required. Where water comes from fully protected
catchment areas, very little treatment is required – just
disinfection. In other cases, more intensive treatment
processes may be required to ensure the drinking water
delivered to every house is safe and aesthetically pleasing.
Groundwater, which is pumped from underground aquifers,
can be treated to remove dissolved gases, iron, manganese,
colour and turbidity. In Perth, groundwater treatment plants at
Jandakot, Wanneroo, Lexia, Mirrabooka and Gwelup oxidise
the water (via aeration and/or chlorination) to increase the
amount of dissolved oxygen and remove both carbon dioxide
and hydrogen sulphide. A coagulant (alum) is also added, that
increases the settling of fine particles caused by iron and
natural organic matter. Clarified water then passes through
sand filters to remove any remaining particles. Similar
processes occur in many country supplies.
At Neerabup Water Treatment Plant, technology has been
introduced to soften the water and reduce salinity. This is the
first time this process has been applied in the southern
hemisphere, and reduces the problems of scale in kettles and
hot water systems, and soap that fails to lather. Naturally
occurring organic substances present a problem for many
water sources because they add colour to the water, which can
increase taste and odour and provide precursors for
disinfection by-products. Since 2001, we have used a water
treatment technology known as MIEX (magnetised ion
exchange) to prevent an intermittent “swampy” odour
occurring in treated groundwater supplied to Perth’s northern
suburbs. Unlike conventional processes, MIEX resin more
effectively removes dissolved organic carbon (DOC) from
drinking water, the source of the odour and taste concerns.
How is your water treated?
Schematic showing the MIEX treatment process
28 Drinking Water Quality Annual Report 2012/13
The schematic figure above shows how the resin mixes with
raw water in the stirred contactors. In the contactors, the
resin rapidly adsorbs DOC from the raw water. In the settler,
the resin (with attached DOC) is then separated from the
treated water. Since commissioning, the MIEX Treatment Plant
has provided a considerable reduction in swampy odour
contact from customers supplied from the Wanneroo
Groundwater Treatment Plant.
Desalination
Desalination, using reverse osmosis, has been used in Denham
for many years, to treat brackish groundwater. Reverse
osmosis was the desalination process chosen for both the 45
gigalitre per year Perth Seawater Desalination Plant, which has
been operational since November 2006 and the Southern
Seawater Desalination Plant, which began supply ahead of
schedule in September 2011.
Similar technology exists at
Leonora and Gascoyne Junction
to improve the aesthetic water
quality (hardness and total
dissolved solids). Other
methods of desalination
available include Electrodialysis
Reversal (EDR) installed at
Wiluna during 2009.
Ultra-filtration
Ultra-filtration treatment is a form of membrane filtration
where source water is forced through a semi-permeable
membrane. It is designed to remove suspended solids,
bacteria, viruses and other pathogens to produce water with
very high purity.
Ultra-filtration is being used at Wyndham, Harding Dam,
Pemberton, Denmark, Margaret River, Hyden, Walpole,
Gascoyne Junction, Salmon Gums, Greenbushes and Kirup.
Disinfection
Disinfection is our primary barrier against harmful pathogenic
bacteria and viruses in our water supply systems. Chlorination
is the most common form of disinfection we use, along with
other water utilities throughout the world. The chlorine dose is
maintained within a narrow range to ensure adequate
disinfection is achieved while only having a minimal effect on
the taste of our water.
Other forms of disinfection include chloramination and
ultraviolet light. Chloramination involves the use of chlorine
and ammonia to produce a longer lasting disinfectant.
Chloramination is used in the Goldfields and Agricultural Water
Supply Scheme to maintain a disinfectant residual along the
length of the extensive pipe network. Ultraviolet light is used
in combination with chlorination at some towns. Reverse Osmosis racks, Newman
29 Drinking Water Quality Annual Report 2012/13
Fluoridation
Public water supplies are fluoridated due to the properties of
fluorine which reduce dental cavities. Poor dental health is
extremely debilitating and remains a major public health
concern. Fluoride strengthens the enamel (surface) of teeth
making them more resistant to cavities.
In Western Australia, fluoridation is regulated by the
Fluoridation of Public Water Supplies Act (1966) which is
administered by the Department of Health. The Fluoridation of
Public Water Supplies Advisory Committee (FAC) oversees
fluoridation and makes recommendations to the Minister for
Health who may issue or rescind directives as appropriate.
To maximise the public health benefit from fluoridation the
FAC has initially sought to ensure larger towns with a
population exceeding 3,000 are given priority for fluoride.
Currently, over 90per cent of the state’s population receive the
benefits of fluoridation.
Dose rates have been set to provide consumers with a
prescribed amount of fluoride based on water consumption.
As average water consumption is proportional to ambient
temperatures different dose rates have been set out for
various parts of the state.
A maximum dose rate of 2 milligrams per litres (mg/L) is
prescribed in the Fluoridation of Public Water Supplies Act.
Notwithstanding the Act, the maximum health related criteria
for fluoride is 1.5 mg/L in the 2011 ADWG.
Most water supplies have some natural fluoride concentration
varying from less than 0.1 mg/L in surface waters through to
greater than 1.5 mg/L in some groundwater sources. Hence
the water fluoridation process involves adding or removing
fluoride to the necessary targeted fluoride concentration.
Fluoridated water supplies (see Table 1) are sampled at least
weekly to confirm acceptable fluoridation performance.
Fluoridation performance is reported monthly to the
Department of Health and periodically to the Fluoridation
Advisory Committee and the Advisory Committee for Purity of
Water.
Water fluoridation is supported by the World Health
Organisation, the Australian Dental Association, the Australian
Medical Association and the National Health Medical and
Research Council. Table 1 shows the localities and schemes
which we are required to fluoridate.
30 Title 30 Drinking Water Quality Annual Report 2012/13
Table 1: Localities requiring fluoridation under Fluoridation of Public Water Supplies Act (1966)
Locality
Advisory Committee
recommended fluoride
range
Advisory Committee
recommended optimum
fluoride concentration
LocalityAdvisory Committee
recommended fluoride range
Advisory Committee
recommended optimum
fluoride concentration
Broome 0.6 - 0.8 mg/L 0.7 mg/L Buckland Hill 0.7 - 1.0 mg/L 0.9 mg/L
Derby 0.5 - 0.7 mg/L 0.6 mg/L Foothills 0.7 - 1.0 mg/L 0.9 mg/L
Dunsborough (de-fluoridated)* 0.7 - 1.0 mg/L 0.9 mg/L Greenmount 0.7 - 1.0 mg/L 0.9 mg/L
Esperance 0.7 - 1.0 mg/L 0.9 mg/L Greenmount/Darlington 0.7 - 1.0 mg/L 0.9 mg/L
Exmouth 0.6 - 0.8 mg/L 0.7 mg/L Hamilton Hill 0.7 - 1.0 mg/L 0.9 mg/L
Manjimup 0.7 - 1.0 mg/L 0.9 mg/L Harvey 0.7 - 1.0 mg/L 0.9 mg/L
Hills Direct 0.7 - 1.0 mg/L 0.9 mg/L
Kalgoorlie 0.7 - 1.0 mg/L 0.8 mg/L Lake Thompson 0.7 - 1.0 mg/L 0.9 mg/L
Merriden 0.7 - 1.0 mg/L 0.8 mg/L Lexia 0.7 - 1.0 mg/L 0.9 mg/L
Northam 0.7 - 1.0 mg/L 0.8 mg/L Mandurah 0.7 - 1.0 mg/L 0.9 mg/L
York 0.7 - 1.0 mg/L 0.8 mg/L Melville 0.7 - 1.0 mg/L 0.9 mg/L
Mirrabooka 0.7 - 1.0 mg/L 0.9 mg/L
Collie 0.7 - 1.0 mg/L 0.8 mg/L Mt. Eliza 0.7 - 1.0 mg/L 0.9 mg/L
Katanning 0.7 - 1.0 mg/L 0.8 mg/L Mt. Hawthorn 0.7 - 1.0 mg/L 0.9 mg/L
Narrogin 0.7 - 1.0 mg/L 0.8 mg/L Mt. Yokine 0.7 - 1.0 mg/L 0.9 mg/L
Mundaring 0.7 - 1.0 mg/L 0.9 mg/L
Albany 0.7 - 1.0 mg/L 0.9 mg/L Neerabup 0.7 - 1.0 mg/L 0.9 mg/L
Mt Barker 0.7 - 1.0 mg/L 0.9 mg/L Pinjarra 0.7 - 1.0 mg/L 0.9 mg/L
South Perth/Kewdale 0.7 - 1.0 mg/L 0.9 mg/L
Geraldton 0.7 - 1.0 mg/L 0.8 mg/L Tamworth Hill 0.7 - 1.0 mg/L 0.9 mg/L
Wanneroo 0.7 - 1.0 mg/L 0.9 mg/L
Karratha 0.6 - 0.8 mg/L 0.7 mg/L Waroona 0.7 - 1.0 mg/L 0.9 mg/L
West Yokine 0.7 - 1.0 mg/L 0.9 mg/L
Armadale/Kelmscott 0.7 - 1.0 mg/L 0.9 mg/L Whitfords 0.7 - 1.0 mg/L 0.9 mg/L
Bold Park 0.7 - 1.0 mg/L 0.9 mg/L
*Defluoridation is currently not covered by the Fluoridation Act. The recommended range and optimum concentration have been specified to provide a duty of care target.
Goldfields & Agricultural Water Supply Scheme
Great Southern Towns Water Supply Scheme
Lower Great Southern Towns Water Supply Scheme
Geraldton Regional Water Supply Scheme
West Pilbara Water Supply Scheme
Perth Integrated Water Supply Scheme
31 Title 31 Drinking Water Quality Annual Report 2012/13
The following summaries are intended to assist you to
interpret the results presented in this report. Additional
information can be obtained by referring to the Fact Sheets
contained in the ADWG published by the National Health and
Medical Research Council and our website
www.watercorporation.com.au.
For the purposes of this report, all data are assessed in
relation to the ADWG.
Escherichia coli
Escherichia coli (E. coli) replaced thermotolerant coliforms as
the key indicator of microbiological performance during
2010/11. E. coli are a subgroup of thermotolerant coliforms
and a more specific indicator for faecal contamination. Any
detection of E. coli is responded to immediately to ensure
water supplied to customers is free of any potential
microbiological contamination.
Thermophilic Naegleria
Thermophilic Naegleria refers to a group of amoebae which
includes Naegleria fowleri, the organism that causes the
waterborne disease primary amoebic meningoencephalitis. In
the context of this report, Thermophilic Naegleria refers to
those tolerant to 42°C. Any detection of Thermophilic
Naegleria is responded to immediately to ensure the risk to
public health is minimised. For information on the Department
of Health’s Naegleria protocol please refer to their website.
Fluoride
Fluorine is one of the most
abundant elements in the
Earth’s crust, and is typically
found as the fluoride ion or
as organic or inorganic
fluorides. It is found
naturally in groundwater
supplies, and is present in
most food and beverage
products and toothpaste.
Additional fluoride is added
to a number of water
supplies in Western Australia
as directed by the Minister for Health (refer to “Fluoridation”
on page 29). The fluoride concentration after dosing is set by
the Fluoridation of Public Water Supplies Advisory Committee,
and does not exceed 1 mg/L. Notwithstanding this, the ADWG
health guideline for fluoride is 1.5 mg/L, applicable to both
fluoridated and non-fluoridated localities.
Nitrate
In Western Australia, elevated nitrate concentrations are
usually due to the natural process of plant decay underground
Fluoride injection point, Perth Seawater Desalination Plant
Understanding water quality test results
32 Drinking Water Quality Annual Report 2012/13
that has occurred over geological time. The ADWG specify a
health guideline of 11.3 mg/L (measured as nitrogen) for
infants less than three months old and a guideline of 22.6
mg/L (measured as nitrogen) for adults and children over
three months old. Nitrate poisoning is very rare and to date no
case, due to nitrate in drinking water, has been recorded in
Western Australia. Where the nitrate concentration is between
11.3 and 22.6 mg/L, and there is no alternative supply, water
providers may apply to the Department of Health for an
exemption from the guideline.
The following localities have been granted exemption from
compliance with the nitrate guidelines by the Department of
Health:
• Mid West Region - Cue, Meekatharra, Mt Magnet,
Nabawa, New Norcia, Sandstone, Wiluna and Yalgoo.
• Goldfields and Agricultural Region - Laverton, Leonora
and Menzies.
In these towns, the Community Health Nurse provides advice
to nursing mothers regarding the use of alternative water for
the preparation of bottle feeds. We provide bottled water free
of charge via the Community Health Nurse as required.
Trihalomethanes
Trihalomethanes (THMs) are present in drinking water as a by-
product of disinfection using chlorination (and chloramination
to a lesser extent). We are required to comply with the ADWG
health guideline of 0.25mg/L expressed as an average long
term exposure. For the purposes of this report, THM
compliance is assessed comparing the guideline with the mean
annual THM concentration.
Alkalinity (as calcium carbonate)
Alkalinity is a measure of the parameters in water that have
acid-neutralising ability, typically expressed in mg/L of
equivalent calcium carbonate. Alkalinity can be affected by
naturally occurring minerals or water treatment chemicals.
There are no aesthetic or health considerations for alkalinity,
and therefore the ADWG 2011 do not provide any guideline
values.
Aluminium (acid-soluble)
Acid-soluble aluminium in water primarily originates from the
addition of coagulants such as aluminium sulphate or poly-
aluminium chloride in the water treatment process. These
coagulants are added to aid the removal of colour and
turbidity. Aluminium can accumulate in pipe sediments, and be
re-suspended during periods of rapid changes to flow patterns.
The ADWG specify an aesthetic guideline of 0.2 mg/L. No
health guideline is set.
Chloride
33 Drinking Water Quality Annual Report 2012/13
Chloride is present in natural waters from the dissolution of
salt deposits. In surface water, the concentration of chloride is
typically less than 100 mg/L while groundwater can have
higher concentrations, particularly if there is salt water
intrusion. In Australian drinking water supplies chloride levels
range up to 350 mg/L depending on local source
characteristics.
Chloride is essential for humans and animals. It contributes to
the osmotic activity of body fluids. Based on aesthetic
considerations, the chloride concentration in drinking water
should not exceed 250 mg/L (ADWG 2011).
Hardness (as calcium carbonate)
Hard water requires more soap to obtain a lather. It can also
cause scale to form on hot water pipes and fittings. Hardness
is caused by the presence of dissolved calcium and
magnesium. Water with hardness:
• Less than 60 mg/L is soft and possibly corrosive
(depends on pH, alkalinity and dissolved oxygen
concentration),
• Between 60 and 200 mg/L is deemed good quality for
all domestic uses,
• Between 200 and 500 mg/L will increase scale
formation and
• Greater than 500 mg/L will cause high scaling.
Hardness can be an important issue when purchasing
appliances such as dishwashers. To convert the hardness
values presented in this report to dH (German degree) units,
divide by 17.8. To convert hardness to millimol (mmol) units,
divide by 100 and to convert to milliequivalent (mEq) divide by
50.The ADWG specify an aesthetic hardness guideline of 200
mg/L.
Iron
Iron occurs naturally in water as a result of contact with soil or
rock in the catchment. It can accumulate in pipe sediments,
and be re-suspended during periods of rapid changes to flow
patterns. Elevated concentrations cause discoloured water and
can stain laundry. The ADWG specify an aesthetic guideline of
0.3 mg/L.
Manganese
Manganese in water can come from contact with soil or rock in
the catchment. It can accumulate in pipe sediments, and be
re-suspended during periods of rapid changes to flow patterns.
Elevated manganese can make water look black and stain
laundry. The ADWG specify an aesthetic guideline of 0.1 mg/L.
pH
pH is a measure of water acidity (pH 7 is neutral). The ADWG
specify a lower and upper aesthetic value of 6.5 and 8.5
respectively. The guidelines allow for a pH of up to 9.2 for new
34 Drinking Water Quality Annual Report 2012/13
concrete tanks and cement-lined pipes, which can significantly
increase the pH for a short period of time. Elevated pH is often
caused by calcium carbonate leaching from the protective
cement lining of the pipes after long transit times. This
characteristic is found at a number of localities on our large
water supply schemes. Where low pH is experienced, this is
typically a consequence of the source characteristic rather
than the influence of treatment. Buffering is a treatment
process that stabilises the pH of the water.
Silica
In Australia, dissolved silica can range between 0.6 mg/L in
some surface waters to 110 mg/L in ground waters. Dissolved
silica can precipitate on some surfaces forming a white
residue. In cases where customer complaints occur due to
scale build-up, water hardness and silica concentrations are
often identified as the primary cause. There is no adverse
health considerations associate with silica in drinking water,
but to minimise scale build up on surfaces silica should not
exceed 80 mg/L (ADWG 2011).
Sodium
Sodium is widespread in water due to the high solubility of
sodium salts and the abundance of mineral deposits. In major
Australian reticulated supplies, sodium concentrations range
from 3 mg/L to 300 mg/L. While sodium is essential to human
life, there is no agreed minimum daily intake level. Based on
aesthetic consideration the concentration of sodium in drinking
water should not exceed 180 mg/L (ADWG 2011).
Total Dissolved Solids
Total Dissolved Solids (TDS) consist of inorganic (natural) salts
and small amounts of organic matter dissolved in water. Total
dissolved solids comprise sodium, potassium, calcium,
magnesium, chloride, sulphate, bicarbonate, carbonate, silica,
organic mater, fluoride, iron, manganese, nitrate and
phosphate.
Water with low TDS can taste flat, while water with high TDS
tastes salty and causes scaling in pipes, fittings and household
appliances. The ADWG provide guidance in the palatability of
drinking water according to TDS concentration:
• Between 0 and 600 mg/L is good quality
• 600 to 900 mg/L is fair
• 900 to 1200 mg/L is poor, and
• Greater than 1200 mg/L, TDS is
unacceptable/unpalatable.
The ADWG guideline of 600 mg/L is based on taste.
True colour
Colour in water originates mainly from natural drainage
through soil and vegetation in a catchment. Corroding metal
pipes can also discolour the water, with iron producing a
brownish colour and copper a faint blue colour. The ADWG
35 Drinking Water Quality Annual Report 2012/13
specify an aesthetic guideline of 15 TCU (True Colour Units).
As a guide, 15 TCU is just noticeable in a glass.
Turbidity
Turbidity is the cloudy appearance of water caused by the
presence of suspended matter. The ADWG specify an aesthetic
guideline of 5 Nephelometric Turbidity Units (NTU) which is
just noticeable in a glass of water.
Summary table and sample groups
Appendix A contains a list of the constituents within the
metals, hydrocarbons, pesticides, radiological and chemical
(other) sample groups, and their respective guideline values,
and sampling location.
36 Title 36 Drinking Water Quality Annual Report 2012/13
Health related performance
Again we have achieved excellent microbiological performance
in 2012/13 with 100 per cent of schemes complying with the
Escherichia coli requirement which is the most important
indicator of faecal contamination (see graph below).
Compliance with health-related chemical guidelines is also high
with 100 per cent of all schemes meeting the guidelines. As
most chemical guidelines are based on lifetime exposure and
have large safety factors, an occasional result outside the
guidelines does not mean the water is unsafe to drink. For this
report, compliance is met if the mean chemical concentrations
for the year are less than the guideline value.
However, if a sample result exceeds the maximum
concentration recommended in the ADWG, it is responded to
quickly and appropriate remedial action undertaken.
The Department of Health is notified of all exceptions and is
closely involved in the response process.
Non-health (aesthetic) related performance
While we strive to meet the ADWG for aesthetic
characteristics, this is very difficult to achieve in a state as
vast as Western Australia with a wide variety of water sources.
This is especially the case in some of our small country water
supplies where there can be few sources of drinking water
available and where installation of treatment can be very
costly. We are committed to improving all aspects of drinking
water quality, however, improvements in aesthetic water
quality are often hard to achieve. The State Government
(through the Ministers for Health and Water) has recognised
that meeting the aesthetic requirements of the ADWG will
require considerable expenditure and may take many years.
Detailed performance review for 2012/13
Performance at a glance
37 Drinking Water Quality Annual Report 2012/13
Appendix C shows a detailed summary of test results for each
scheme throughout the state. The following graph shows the
overall aesthetic performance for 2012/13. The left-hand bar
shows the percentage of 245 schemes where the mean
concentration for the year is less than the aesthetic guidelines.
In 2012/13, around 64 per cent (157 out of 245) of our
schemes met all of the aesthetic guidelines. The right-hand
bar shows our performance for all aesthetic analyses
(aluminium, true colour, hardness, iron, manganese, pH, TDS,
turbidity, sodium, chloride, sulphate and silica) across our 245
schemes. Our total performance was 95 per cent, with 10,297
out of 10,868 analyses complying with the aesthetic
guidelines.
The results in Appendix C show a relatively small number of
excursions above the guidelines in aesthetic quality. These
excursions are caused by the unique quality of local sources,
lack of alternative sources, impact of the drying climate on
groundwater production and abstraction from groundwater in
proximity to the coast.
For many schemes, these excursions have only minimal
influence on the taste of the drinking water.
The graph below shows the challenge of supplying
aesthetically pleasing drinking water to many smaller towns
with limited available water resources.
38 Drinking Water Quality Annual Report 2012/13
Health performance review 2009 to 2013
For the past five years, the microbiological performance has
been excellent with 100 per cent of the metropolitan and
country localities complying with the Escherichia coli (or
thermotolerant coliform) requirements. For chemical-health,
there is similar high performance over this period.
39 Title 39 Drinking Water Quality Annual Report 2012/13
Customer contacts
Water quality related customer contacts (enquiries and
complaints) are recorded and monitored continuously to
identify any trends and areas for improvement. In 2012/13
our Operations Centre received 7,724 water quality related
customer contacts (compared with 7,898 in 2011/12). Below
shows the breakdown of these.
For customer contacts regarding poor water quality (water
quality faults) our Customer Charter states we will respond
within two hours or at an agreed time. We have an agreed
customer and business target of 95 per cent. In 2012/13 once
a fault was recorded we responded to 95.4 per cent within the
target of two hours (see figure below).
Customer research
Customer expectations
40 Drinking Water Quality Annual Report 2012/13
We measure community perceptions of the quality of their
drinking water through our quarterly Customer Performance
Index (CPI) survey. In this survey, customers are asked to
indicate the degree to which they either agree or disagree with
two statements in relation to water quality (where 1 is ‘poor’
and 10 is ‘excellent’). The average rating for these two statements in June 2013 was 7.1 and previous survey results
are shown below.
Survey Questions September 2012 December 2012 March 2013 June 2013
How would you rate the Water Corporation on
providing an acceptable standard of water quality?
6.7 7.2 7.2 7.0
How would you rate the Water Corporation on
providing a consistent level of water quality?
6.8 6.7 6.8 7.1
Average scores 6.8 7.0 7.0 7.1
41 Title 41 Drinking Water Quality Annual Report 2012/13
Monitoring and reporting improvements
We have been strengthening our operational monitoring to
ensure continual barrier risk assessments, as prompted by the
ADWG revision. Extensive work has been undertaken on our
Locality Barrier Tool project which allows continuous visibility
of the critical processes during water treatment stages. Work
is still in progress but has already assisted in identifying areas
of progression for our capital project programs.
Water quality capital improvements
We have embarked on an extensive program of water quality
capital improvements. These projects ensure robust multiple
barriers to contamination are in place from “catchment to tap”
for all our schemes. Examples of work undertaken are
described through the following
sections.
Monitoring and control
systems
Installation of instrumentation
that allows continuous
monitoring of key water quality
parameters at each water supply
ensures unsatisfactory
performance is detected quickly
and remedial actions initiated.
Chlorination
We have begun a state-wide chlorination program to upgrade
all chlorinators to the latest corporate standards which
includes a body of work to modernise older chlorinators that
were not replaced in the original ADWG program.
Improvements will ensure enhanced alarming, automation and
reporting capability.
Water treatment
New treatment plants, and upgrades to existing plants,
continue to be installed in order to meet the lower chemical
concentrations recommended by the ADWG and to provide an
additional barrier to microbiological contamination.
Picton Water Treatment Plant was completed in 2012 and the
plant is now providing a significant contribution to the
Australind/Eaton schemes. The Picton plant is providing highly
treated water, importantly including iron removal to reduce
discoloured water, from a redeveloped Yarragadee bore.
Ensuring safe drinking water during times of crises
We have five mobile emergency ultra-filtration plants which
allow us to rapidly restore high quality drinking water supplies.
In the past, the only practical option was to transport drinking
water by road tankers to affected areas. These plants are
mobilised quickly to provide a minimum of 500,000 litres of
high quality water per day. Other treatment units are available
for specialised applications including a reverse osmosis unit. Water Corporation staff, Perth Seawater Desalination Plant
Improving your water quality
42 Drinking Water Quality Annual Report 2012/13
In 2012/13 mobile units were deployed in Salmon Gums,
Kirup, Greenbushes, and Gascoyne Junction. Units were also
deployed to Manjimup last summer but are now on standby for
the coming summer pending the final yield from this winter
and the impact of a new pipeline bringing water from a
Yarragadee Bore near Nannup.
Tank roofs
Construction, repair or replacement of roofs on all reservoirs
and tanks ensures stored water cannot be contaminated with
rainwater or pests and vermin.
Pipes and pipelines
Construction of new pipelines and modification to the flow of
water through tanks and reservoirs prevents stagnation of
water in storage.
Disinfection in long pipes
A major corporate project has been running for eight years to
improve the persistence of chloramine through the long
pipelines of the Goldfields and Agricultural Water Supply
(GAWS), the only chloraminated water supply system in
Western Australia. This has involved a series of detailed
investigations across the scheme. One component included
determining the areas of nitrification, which is when natural
aquatic bacteria within the pipelines convert ammonia to
nitrite, causing a reduction in the extent of effective
disinfection. We have been working internally, and with
Research Organisations to overcome this issue.
Measures that have been taken to expand the maintenance of
chloramine and chlorine residuals further into the distribution
system have included the installation of numerous chlorine
and ammonia dosing plants at strategic points in the system.
Modifications have also been made to many of the tanks by
installing specially designed separate inlets to each tank to
ensure complete mixing. This, together with operating at lower
water levels in the tanks during the winter low demand period,
minimises water stagnation and loss of residuals. These
measures have succeeded in significantly improving the water
quality of the supply on the GAWS.
Goldfields Pipeline
43 Drinking Water Quality Annual Report 2012/13
ConstituentHealth Guideline
(mg/L)Guideline Sampling Location Constituent
Health Guideline
(mg/L)Guideline Sampling Location
2,4,5-trichlorophenoxyacetic acid 0.1 2011 Reticulation System Fluometron 0.05 2011 Reticulation System
2,4-dichlorophenoxyacetic acid 0.03 2011 Reticulation System Heptachlor & heptachlor epoxide (total) 0.0003 2011 Reticulation System
Aldrin 0.0003 2011 Reticulation System Hexachlorobenzene * 2011 Reticulation System
Atrazine 0.02 2011 Reticulation System Hexazinone 0.3 2011 Reticulation System
Azinphos-methyl 0.003 2011 Reticulation System Lindane 0.01 2011 Reticulation System
Bromophos-ethyl 0.01 2011 Reticulation System Maldison 0.05 2011 Reticulation System
Chlordane 0.002 2011 Reticulation System Methoxychlor 0.3 2011 Reticulation System
Chlorothalonil 0.03 2011 Reticulation System Metolachlor 0.3 2011 Reticulation System
Chlorpyrifos 0.01 2011 Reticulation System Metsulfuron-methyl 0.03 2011 Reticulation System
Clopyralid 1 2011 Reticulation System Molinate 0.005 2011 Reticulation System
DDT (total isomers) 0.009 2011 Reticulation System Parathion-ethyl 0.01 2011 Reticulation System
Diazinon 0.003 2011 Reticulation System Parathion-methyl 0.1 2011 Reticulation System
Dicamba 0.1 2011 Reticulation System Picloram 0.3 2011 Reticulation System
Diclofop-methyl 0.005 2011 Reticulation System Propazine 0.05 2011 Reticulation System
Dieldrin 0.0003 2011 Reticulation System Propiconazole 0.1 2011 Reticulation System
Dimethoate 0.05 2011 Reticulation System Simazine 0.02 2011 Reticulation System
Diuron 0.03 2011 Reticulation System Terbutryn 0.3 2011 Reticulation System
Endosulfan 0.03 2011 Reticulation System Triclopyr 0.1 2011 Reticulation System
Ethion 0.003 2011 Reticulation System Trifluralin 0.05 2011 Reticulation System
Fenitrothion 0.01 2011 Reticulation System
Pesticides
* The guidelines state there is insufficient data to set a guideline based on health considerations
Appendix A – List of parameters
within sampling groups
44 Drinking Water Quality Annual Report 2012/13
ConstituentHealth Guideline
(mg/L)Guideline Sampling Location Constituent
Health Guideline
(mg/L)Guideline Sampling Location
Benzene 0.001 2011 Reticulation System Hexachlorobutadiene 0.0007 2011 Reticulation System
Carbon tetrachloride 0.003 2011 Reticulation System Nitrilotriacetic acid (NTA) 0.2 2011 Reticulation System
Chlorobenzene 0.3 2011 Reticulation System Organotins 2011 Reticulation System
Dichlorobenzenes 2011 Reticulation System Tributyltin oxide 0.001 2011 Reticulation System
1,2-dichlorobenzene 1.5 2011 Reticulation System Plasticisers 2011 Reticulation System
1,3-dichlorobenzene * 2011 Reticulation System di(2-ethylhexyl) phthalate (DEHP) 0.01 2011 Reticulation System
1,4-dichlorobenzene 0.04 2011 Reticulation System Polycyclic aromatic hydrocarbons (PAHs) 2011 Reticulation System
Dichloroethanes 2011 Reticulation System Benzo(a)pyrene 0.00001 2011 Reticulation System
1,2-dichloroethane 0.03 2011 Reticulation System Styrene (vinylbenzene) 0.03 2011 Reticulation System
Dichloroethenes 2011 Reticulation System Tetrachloroethene 0.05 2011 Reticulation System
1,1-dichloroethene (1,1-DCE) 0.03 2011 Reticulation System Toluene 0.8 2011 Reticulation System
1,2-dichloroethene (1,2-DCE) 0.06 2011 Reticulation System Trichlorobenzenes (total) 0.03 2011 Reticulation System
Dichloromethane 0.004 2011 Reticulation System Trichloroethylene (TCE or trichloroethene) * 2011 Reticulation System
Ethylbenzene 0.3 2011 Reticulation System Vinyl chloride 0.0003 2011 Reticulation System
Ethylenediamine tetraacetic acid (EDTA) 0.25 2011 Reticulation System Xylene 0.6 2011 Reticulation System
Hydrocarbons
* The guidelines state there is insufficient data to set a guideline based on health considerations
45 Drinking Water Quality Annual Report 2012/13
In addition to the above specific analyses, screening for a
large number of other pesticides is undertaken on all samples
(refer Appendix B for full list). Any detection is further
analysed and the result reported to the Water Corporation.
Other Health-related Chemicals
This group currently includes Cyanide (health guideline of
0.08 mg/L) and Iodide (health guideline of 0.5mg/L).
ConstituentHealth
Guideline
(mg/L)
Guideline Sampling Location
Antimony 0.003 2011 Reticulation System
Arsenic 0.01 2011 Reticulation System
Barium 2 2011 Reticulation System
Beryllium 0.06 2011 Reticulation System
Boron 4 2011 Reticulation System
Cadmium 0.002 2011 Reticulation System
Chromium (as Cr[VI]) 0.05 2011 Reticulation System
Copper 2 2011 Reticulation System
Lead 0.01 2011 Reticulation System
Mercury 0.001 2011 Reticulation System
Molybdenum 0.05 2011 Reticulation System
Nickel 0.02 2011 Reticulation System
Selenium 0.01 2011 Reticulation System
Silver 0.1 2011 Reticulation System
Uranium 0.017 2011 Reticulation System
Zinc * 2011 Reticulation System
Metals
* The guidelines state there is insufficient data to set a guideline based on health considerations
46 Drinking Water Quality Annual Report 2012/13
This appendix lists all constituents for which we routinely sample. Additional information is available by telephoning us on 13 13 75
Acrylamide Dichloromethane 2,4,5-trichlorophenoxyacetic acid Heptachlor & heptachlor epoxide (total)
Benzene Ethylbenzene 2,4-dichlorophenoxyacetic acid Hexachlorobenzene
Carbon tetrachloride Ethylenediamine tetraacetic acid (EDTA) Aldrin Hexazinone
Chloroacetic acids Epichlorohydrin Atrazine Lindane
Chloroacetic acid Hexachlorobutadiene Azinphos-methyl Maldison
Dichloroacetic acid Nitrilotriacetic acid (NTA) Bromophos-ethyl Methoxychlor
Trichloroacetic acid Organotins Chlordane Metolachlor
Chlorobenzene Tributyltin oxide Chlorothalonil Metsulfuron-methyl
Chlorophenols Plasticisers Chlorpyrifos Molinate
2-chlorophenol di(2-ethylhexyl) phthalate (DEHP) Clopyralid Parathion-ethyl
2,4-dichlorophenol Polycyclic aromatic hydrocarbons (PAHs) DDT (total isomers) Parathion-methyl
2,4,6-trichlorophenol Benzo(a)pyrene Diazinon Picloram
Dichlorobenzenes Styrene (vinylbenzene) Dicamba Propazine
1,2-dichlorobenzene Tetrachloroethene Diclofop-methyl Propiconazole
1,3-dichlorobenzene Toluene Dieldrin Simazine
1,4-dichlorobenzene Total Trihalomethanes Dimethoate Terbutryn
Dichloroethanes Trichloroacetaldehyde (chloral hydrate) Diuron Triclopyr
1,2-dichloroethane Trichlorobenzenes (total) Endosulfan Trifluralin
DichloroethenesTrichloroethylene (TCE or
trichloroethene)Ethion
1,1-dichloroethene (1,1-DCE) Vinyl chloride Fenitrothion
1,2-dichloroethene (1,2-DCE) Xylene Fluometron
Organic Compounds Pesticides
Appendix B – List of all sampling
parameters
47 Drinking Water Quality Annual Report 2012/13
Physical Characteristics Microbiological Radiological
Aluminium (acid soluble aluminium) Hardness (Ca, Mg) Escherichia coli Radium 226 & 228
Antimony pH Naegleria tolerant to >42°C Radon 222
Arsenic Total dissolved solids (calculated)
Barium True colour
Beryllium Turbidity
Boron
Cadmium
Chloride
Chromium (as Cr[VI])
Copper
Cyanide
Fluoride
Iodide
Iron
Lead
Manganese
Mercury
Molybdenum
Nickel
Nitrate / Nitrite
Selenium
Silicon
Silver
Sodium
Sulphate
Uranium
Zinc
Inorganic Chemicals
48 Drinking Water Quality Annual Report 2012/13
Perth Metropolitan Region
Health-related Tables 1 and 2
Aesthetic Tables 3 and 4
Mid West Region
Health-related Tables 5 and 6
Aesthetic Tables 7 and 8
Goldfields and Agricultural Regions
Health-related Tables 9 and 10
Aesthetic Tables 11 and 12
South West Region
Health-related Tables 13 and 14
Aesthetic Tables 15 and 16
Great Southern Region
Health-related Tables 17 and 18
Aesthetic Tables 19 and 20
North West Region
Health-related Tables 21 and 22
Aesthetic Tables 23 and 24
Appendix C – Summary of test
results
49 Drinking Water Quality Annual Report 2012/13
The information contained in the maps of this report is the exclusive
property of the Water Corporation and the respective copyright
owners. It is subject to ongoing review and should be viewed in
conjunction with the associated materials. No part of this production
should be copied, modified, reproduced or published in any form
other than that intended by the author. The respective data owners,
other than the Water Corporation, are acknowledged below:
Public Drinking Water Source Areas (Department of Water)
Hydrography Linear Hierarchy (Department of Water)
Road Centrelines (Landgate)
Townsites (Landgate)
Australian Coastline (Geoscience Australia)
The following metadata applies to all 6 maps:
Author: Drinking Water Quality Branch, Water Corporation of WA
Date created: 18 October 2013
Coordinate System: Geographic Coordinate System, GDA 1994
Vertical Datum: Australian Height Datum (AHD)
Original map names and AquaDoc numbers:
GAR_DWQB report map_v2.mxd (AquaDoc # 9510417)
GSR_DWQB report map_v2.mxd (AquaDoc # 9510418)
MR_DWQB report map_v2.mxd (AquaDoc # 9510420)
MWR_DWQB report map_v2.mxd (AquaDoc # 9510421)
NWR_DWQB report map_v2.mxd (AquaDoc # 9510422)
SWR_DWQB report map_v2.mxd (AquaDoc # 9510424)
Appendix D – Supporting information
for water source location maps