Impervious Area Charge

DC Water has changed the way we calculate your sewer charges. We have lowered the rate for sewer service and are now including a special charge for properties that include surfaces water can't penetrate (impervious surfaces).

Impervious surfaces such as rooftops, paved driveways, patios, and parking lots, are major contributors to rainwater runoff entering the District's sewer system. They also add significantly to pollution in the Anacostia and Potomac rivers and Rock Creek.

The new Clean Rivers Impervious Area Charge (CRIAC) is a fair way to distribute the cost of maintaining storm sewers and protecting area waterways because it is based on a property's contribution of rainwater to the District's sewer system. Because charges are based on the amount of impervious area on a property, owners of large office buildings, shopping centers and parking lots will be charged more than owners of modest residential dwellings.

All residential and non-residential customers are billed for CRIAC. The FY 2015 monthly CRIAC is $16.75 per equivalent residential unit (ERU).

Frequently Asked Questions

The Clean Rivers Impervious Area Charge is part of DC Water's 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 of Columbia.

Map highlighting impervious surface areas: driveways, private walks, roof tops, and parking lots
Map highlighting impervious surface areas:
driveways, private walks, roof tops, and parking lots
  1. What is an Clean Rivers Impervious Area Charge (CRIAC)? The CRIAC is based upon the amount of impervious surface on your property. An impervious surface is a man-made surface that cannot be easily penetrated by water, such as
    • rooftops,
    • driveways,
    • patios,
    • tennis courts,
    • swimming pools,
    • parking lots,
    • and other paved or covered areas (regardless of materials used).

    Impervious surface areas are a major contributor to rainwater runoff entering the District's sewer system and pollution entering area waterways.

  2. Why is the CRIAC necessary? The charge is necessary to recover the costs of the $2.6 billion federally mandated Clean Rivers Project detailed in the "What We Do" area of this site. The 20-year plan will reduce the discharge of excess flows into local waterways from DC Water combined sewer system.
  3. Why did DC Water decide to defray the costs of the Clean Rivers Project in this manner? The DC Water Board of Directors determined that the CRIAC is a more equitable way to recover the costs of the Clean Rivers Project than the volumetric charge (for water used), because the CRIAC is based on a property's contribution to rainwater runoff.
  4. How is the amount of the charge determined? The charge is based on an Equivalent Residential Unit (ERU). An ERU is a statistical median of the amount of impervious surface area in a single-family residential property, measured in square feet. The FY 2015 monthly ERU value is $16.75.
  5. Residential Customers: Beginning in FY 2011, all residential customers will be assessed ERUs based upon the amount of impervious surface on their property and the following six-tier rate structure:

    Impervious Area (Square Feet) ERU ERU Rate Monthly Cost
    100-600 0.6 $16.75 $10.05
    700-2,000 1.0 $16.75 $16.75
    2,100-3,000 2.4 $16.75 $40.20
    3,100-7,000 3.8 $16.75 $63.65
    7,100-11,000 8.6 $16.75 $144.05
    11,100 and more 13.5 $16.75 $226.13

    All nonresidential customers are assessed ERUs based on the total amount of impervious surface on each lot.

  6. Why did DC Water develop a Tiered Rate structure for residential customers?

    The tiers were developed in order to bill residential customers more equitably, based on the size of their properties.

  7. If I do not agree with the square footage for which DC Water is billing me, how can I appeal? You may follow the bill dispute process located on the back of your bill.
  8. How was the square footage determined for my property? It was measured using the geographical information system data from DC GIS and Office of the Surveyor.
  9. Is there a discount for residents who implement measures to mange and/or reduce wet weather runoff? To apply for the IAC Incentive Program, and receive more information on the District Department of Environment's Riversmart Rewards Program, visit their website here.
  10. If You Have Questions or Comments

    Email info@dcwater.com
    Phone 202-354-3600
    Fax 202-787-2795
    Mail Customer Service
    810 First St., NE, Suite 1100
    Washington, DC 20002

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