Updated Estimates of Impervious Area, Equivalent Residential Units, IA Rate,

and Customer Bill Impacts

AOBA

October 27, 2008

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IMPERVIOUS AREA SURFACE CHARGE

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WHAT IS THE IMPERVIOUS SURFACE AREA CHARGE

• WASA is implementing an impervious surface area charge to more equitably allocate the costs of the CSO Long Term Control Plan through a charge based upon contribution to surface runoff from wet weather events.

• Go live date “April 2009”.

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• Impervious Surface Area is an area that does not allow water to easily penetrate such as rooftops, paved driveways, patios, and parking lots.

• This cost is currently being recovered through the sewer charge “volumetric”.

• The amount of impervious area on each property will be determined from information contained in the District of Columbia’s GIS.

• Initially, all residential customers will be charged based upon one ERU (Equivalent Residential Unit): a simplified billing that represents a typical house.

– 1 ERU = 1000 square feet of impervious surface.

– The WASA Board of Directors is exploring an incentive program for future incorporation into the rate structure.

WHAT IS THE IMPERVIOUS SURFACE AREA CHARGE, (Cont.)

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PROJECT BACKGROUND AND UNDERSTANDING

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Combined Sewer Overflow (CSO) Long-Term Control Plan

2005 Federal twenty-year $2.2 billion program

Consent decree Facility planning and

geotechnical work has begun Projected to reduce 96% of CSOs

98% reduction on Anacostia River

Plan includes: 3 large storage tunnels Pumping station improvements Targeted sewer separation Consolidation/elimination of several outfalls Low Impact Development projects

Nine Minimum Control CSO improvements ($140 million) completed by 2008; reduce 40% of CSOs Received federal funding of about $106 million to date

• Future additional funding of $14m has been proposed for FY 2009

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Updated Estimates of Impervious Area, Equivalent Residential Units, IA Rate,

and Customer Bill Impacts

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Impervious Area Statistics

• This work improves upon analysis previously provided in 2003, 2005 and early in 2008 by utilizing the most recent data sources and by applying the impervious area assignment methods recently established over the entire DC land area.

SF Res Non SF Res Totals

Number of Properties 100,829 29,374 130,203

Total Land Area (mil.Sq.ft) 345.2 886.6 1231.8

Percentage of Total Land Area 28% 72% 100%

Total Impervious Area (mil.Sq.ft) 121.0 330.4 451.4

Percentage of Total (non streets and ROWs) Impervious Area 27% 73% 100%

Average Impervious Area per Property 1,200 11,248 3,467

Median Impervious Area per SF Residential Property 990

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Comparison of Share of ERUs to Share of Water Consumption by Customer Group

Class Share of Equivalent Residential Units (% )

Share of Metered Water Consumption (% )

Single Family Residential 23% 21% Multi-family Residential 13% 22% Commercial 30% 34% Municipal 8% 4% Federal 24% 15% District of Columbia Housing Authority 1% 3% Total 100% 100%

•The table compares the share of impervious area equivalent residential units to the metered water consumption for each customer group.

•An impervious area rate structure will cause a shift in the cost allocation between customer classes due to differences in their water use and the amount of impervious area.

•Multi-family properties will see a major reduction in costs allocated to that group due to the high-density of the land use.

•Federal properties will see a larger portion of costs allocated to them due to same reason as above.

Group

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COS LTCP Costs through 2017

• Based on WASA 2009 - 2017 approved ten-year financial plan

• Includes all WASA approved LTCP costs

• Forecast IAC cost pool – 2009 through 2017

$0

$10,000,000

$20,000,000

$30,000,000

$40,000,000

$50,000,000

$60,000,000

$70,000,000

$80,000,000

$90,000,000

2009 2010 2011 2012 2013 2014 2015 2016 2017

CSO "Cost Pool"

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Monthly Rate Comparisons – With/Without IAB Charges

• FY 2009 approved rates reflects ten-year financial forecast from Fall 2007, including a 7.5% increase in water and sewer rates for FY 2009.

• Table shows the amount of the reduction in sewer rate that could occur with the implementation of the IAB charge.

Approved FY 2009 FY 2009 RateRates w/o IAB w/IAB Rate Change

Exisiting Usage Rate - Water & Wastewater $/CCF Water Rate 2.32$ 2.30$ Sewer Rate 3.47$ 3.30$ (0.17)$

Combined Rate 5.79$ 5.60$ (0.17)$

IAB Charge $/ERU - 1.24$

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Projected Annual Residential IAB Charge Per ERU

IAC Monthly Charge Per ERU

$5.68

$9.49

$11.46

$13.26

$7.21

$3.01

$16.33

$2.20$1.24

$0.00

$2.00

$4.00

$6.00

$8.00

$10.00

$12.00

$14.00

$16.00

$18.00

2009 2010 2011 2012 2013 2014 2015 2016 2017

Imp

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Average Monthly Bill for Residential Customer with Monthly Metered Consumption of 8.33 CCF

Monthly Bill With and Without IA Charge for SF Customer with 8.33 CCF Water Use

$0

$20

$40

$60

$80

$100

$120

Fiscal Year

To

tal

Mo

nth

ly B

ill

No IAB $56.56 $63.59 $73.07 $84.98 $92.08 $97.35 $102.46 $107.86

With IAB $56.22 $63.39 $72.81 $84.48 $91.45 $96.52 $101.46 $106.70

2009 2010 2011 2012 2013 2014 2015 2016

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Average Monthly Bill for Commercial Customer with Monthly Metered Consumption of 998 CCF

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

$14,000

Fiscal Year

To

tal

Mo

nth

ly B

ill

Commercial T-No IAB $6,298.92 $7,140.37 $8,277.17 $9,703.41 $10,554.24 $11,185.80 $11,797.54 $12,409.97

Commercial T-With IAB $6,154.49 $6,933.37 $7,993.37 $9,168.71 $9,874.79 $10,291.99 $10,718.50 $11,161.03

2009 2010 2011 2012 2013 2014 2015 2016

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Average Monthly Bill for Commercial Customer with Monthly Metered Consumption of 15 CCF

$0

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

Fiscal Year

To

tal

Mo

nth

ly B

ill

Commercial S-No IAB $96.38 $109.24 $126.62 $148.42 $161.43 $171.09 $180.44 $189.80

Commercial S-With IAB $378.55 $610.09 $813.32 $1,442.20 $1,805.44 $2,333.75 $2,791.31 $3,211.77

2009 2010 2011 2012 2013 2014 2015 2016

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Rate Impact Calculator

Your Input Estimate for Comparison**

Average bill in October 2008 (adopted 7.5% adjustment) - Input your average water consumption (Ccf) 998 5,758.46$

Average bill after April 2009 incorporating impervious surface charge (not yet proposed) - Input the square footage of your impervious surface area (roofprint only) 36312 5,663.64$ **Water & sewer consumption only. Does not include stormwater, PILOT/ROW or metering fees.

** (8.33 Ccf) average monthly consumption for single family residential property