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Impervious Area Charge
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Separate Impervious Area Charge will appear on DC WASA bills this fall

DC WASA is introducing an Impervious Surface Area billing charge that separates from the current sewer rate the cost of a massive construction project to reduce sewer overflows into local waterways. This charge, appearing on DC WASA bills in April, 2009, is based on the impact that water runoff from individual properties has on the District's sewer system. The actual charge is calculated on the amount of impervious area on the property. Impervious areas are man-made surfaces that cannot be easily penetrated by water such as rooftops, paved driveways, patios, and parking lots.

Frequently Asked Questions

The impervious surface area billing program is an investment in reducing pollution in the Anacostia and Potomac rivers and Rock Creek. The charge applies to all lots, parcels, properties and private streets in the District.

  1. What is an impervious surface area charge? The impervious surface area charge is based upon the amount of impervious surface on your property. Impervious surface area is used as the basis for this charge since it is a major contributor to rainwater runoff entering the District's sewer system. An impervious surface is a man-made surface that cannot be easily penetrated by water such as rooftops, driveways, patios, parking lots and other paved areas, tennis courts, swimming pools, and any path or walkway that is covered by impervious material.

    2. Map highlighting impervious surface areas: driveways, private walks, roof tops, and parking lots

  2. Why is the impervious surface area charge necessary? The charge is necessary to recover the costs of the $2.2 billion federally-mandated Combined Sewer Overflow Long Term Control Plan (CSO LTCP). The 20-year CSO LTCP will reduce the discharge of excess flows into local waterways from the District of Columbia Water and Sewer Authority (DC WASA) combined sewer system. Combined sewer systems were constructed around the turn of the 19th century to carry sanitary sewage and rainwater runoff in the same pipe.

  3. Why did DC WASA decide to allocate the costs of the CSO LTCP in this manner? The cost of combined sewer overflow control has been part of the sewer rate, which is based on the metered amount of water usage. The DC WASA Board of Directors determined that the impervious surface area charge is a more equitable basis to recover the costs of the CSO LTCP than the volumetric charge, since the charge is based on a property's contribution to rainwater runoff.

  4. Why has DC WASA decided to bill for this charge now? The CSO LTCP program is currently underway and the impervious surface area charge is designed to cover program costs. Therefore, the charge is being designed now to reallocate costs from the sewer charge currently appearing on the DC WASA bill to the impervious surface charge. This more appropriately recovers costs from those who most contribute to the need for wet weather management.

  5. How is the amount of the charge determined? The charge is based upon an Equivalent Residential Unit (ERU). An ERU is defined as the amount of impervious surface area measured in square feet based on a statistical median for a single family residential property. Initially, all residential customers will be assessed one (1) ERU. All non-residential customers shall be assessed ERUs based upon the total amount of impervious surface on each lot. This total amount of impervious surface will be converted into ERUs.

  6. Who sets the impervious surface area charge? The DC WASA Board of Directors sets the impervious surface area charge. In FY 2009, each ERU will be billed at $1.24 a month.

  7. Is the impervious surface area charge a one-time fee? No. DC WASA customers will see this charge on their monthly bill beginning April, 2009.

  8. Do other cities have an impervious surface area charge? Yes. Other cities have this charge to cover the cost of managing pollution from rainwater runoff.

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If You Have Questions or Comments

Email
info@dcwasa.com
Phone
202-354-3600
Fax
202-787-2795
Mail
Board Secretary
5000 Overlook Ave., SW
Washington, DC 20032

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