Upcoming DC Stormwater Management Regulation Change


Stormwater management is a hot topic for both private developers and District of Columbia agencies. The Environmental Protection Agency has signaled its intent to adopt demanding rules for retaining stormwater on site - a requirement to retain 1.2 inches of rainwater that falls on site during a 24 hour period  for the District of Columbia. The new standard is particularly challenging since it would require not just temporarily detaining stormwater on site for later discharge into District's sewer system, but actual retention of the water on site in perpetuity. A draft of the EPA's MS4 permit setting that standard has been released and a final version is expected in the next few weeks. Once it is adopted, the District's Department of the Environment will have one year to adopt conforming regulations.

This major federal initiative, as well as other related initiatives, will affect not just private development, but the District's own properties as well. This will include miles of public space consisting of roads, sidewalks and, as well, spaces between private property and adjacent curbs, generally. In addition, DDOE will need to find a way to administer this requirement in a manner that is reasonable and achievable.

This regulatory challenge creates common ground. DCBIA has established working groups with both DDOE and DDOT to explore these issues. DDOE recently convened a large meeting among various stakeholders, including representatives of the environmental community, to brainstorm on possible approaches. One possibility involves a proposal to allow off site mitigation of stormwater management impacts under a system that would require a significant percentage of the 1.2 inch standard to be met on the subject property, while allowing the remaining percentage to be met at another location. The second location might involve public property, as well as private property. Some liken this to the system of trading transfer development rights, but off site stormwater mitigation presents its own challenges that need to be examined.

DCBIA has begun discussions with DDOT on the most effective method of possibly using public space to meet the stormwater retention standards. At this point, most parties are still scratching their collective heads on how to address the proposed regulations. The good news is that the head scratching is accompanied by coordinated discussions among developers, government agencies and other stakeholders on how best to approach this challenge.

Charles K. Barber, Deputy General Counsel
The George Washington University
DCBIA Past President

Replies to this Topic

Finally, another "revenue stream" for us to dip into....now big brother has to pay impervious stormwater runoff fees like the rest of us. This is going to be an enormous job creation tool perhaps even more important that the ARRA recovery act passed last year. Talk about a good way to start the New Year! 

Congress Passes Stormwater Funding Bill

Right before Christmas, Congress passed legislation (S.3481) amending the Clean Water Act and clarifying that the federal government must pay stormwater utility fees to local governments. This may sound kind of mundane, but local stormwater utility fees are an increasingly important way to fund local effort to reduce polluted stormwater runoff.

Here's how it works: a city will set a fee based on a parcel's impervious surface (e.g. rooftops, parking lots, etc.) that generate polluted stormwater runoff and use that money to fund stormwater improvement projects for cleaner water. Stormwater utilities exist throughout the country in places like Minneapolis, Orlando, Bend, Oregon and Philadelphia just to name a few. Most of these fees can be reduced by decreasing the pollution impact of a site by treating and cleaning water on-site, often using green infrastructure techniques. In Milwaukee, for instance, American Rivers staffer Sean Foltz is working to promote the green infrastructure credit as part of the City's stormwater utility fee - a ten acre business parcel stands to save over $15,000 a year by installing green infrastructure practices such as green roofs. Stormwater utility fees also provide an important and steady stream of funding that can allow communities to qualify for additional federal funding - in Philadelphia, the stormwater funds helped secure the city a $30 million loan for green infrastructure from federal clean water infrastructure funds because there was a payback mechanism associated with the City's Greenworks plan.

Unfortunately, the federal government, in Washington DC and around the country, has claimed that it did not have to pay these fees to local governments based on claims of sovereign immunity. In DC this amounts to millions of dollars, but also affects communities across the country: Seattle is owed over a million dollars by several federal agencies, Aurora Colorado is owed almost $150,000 from an Air Force Base, and a metro Atlanta County is due $160,000. 

The new legislation will remedy this problem and ensure that the federal government pays it's fair share for the pollution it creates. A good start for 2011 and while not binding on similar disputes at the state and local level, hopefully this new policy will make clear that a small fee on a pollution source can go a long way for clean water.

For more about stormwater utilities click here.


This is very encouraging.  It is exciting to see the federal government take such an active role in protecting the watershed for communities across the US. Lead first by example ya know!  And I am sure communities that do not have stormwater management fees might be attracted to examine their stormwater policy if the community has some federal facilities now.

Impervious Area Charge & Calculations

I thought that some of you who live in the District might have some questions concerning the Impervious Area Charge that is in place for FY 2011. Also, did you know that WASA may likely raise this fee anywhere from 15-88% annually according to preliminary reports that were prepared when they were looking into using the IAC as a revenue stream to help repair their stormwater infrastructure.

Personally, while I am in favor of using a tool like the IAC to help pay for stormwater improvements it seems a little unfair to residents and business owners on tight budgets to not offer any incentitive programs that might mitigate or reduce these fees. In addition, if you can not project or forecast rate increases over the next five years how can business owners and residents determine a credible ROI or even a simple payback on LID improvements that they might like to incorporate into their properties.

Also, I think that it is interesting to note that even the $3.45 Equivalent Residential Unit (ERU) rate projected for this year went up 15% than what was projected at the beginning of the program that was discussed only two years ago. Is there any way that pressure can be applied to WASA to get them to approve a rate increase schedule for the next ten years or will these fees slowly bleed us every year?

For more information on the IAC program I encourage you to visit WASA's website. http://www.dcwasa.com/customercare/iab.cfm

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 Impervious Area Charge (IAC) 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 commercial customers are billed for IAC. The FY 2011 monthly IAC is $3.45 per equivalent residential unit (ERU).

Frequently Asked Questions

The 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

  1. What is an Impervious Area Charge (IAC)? The IAC 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 areas.
    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 IAC necessary? The charge is necessary to recover the costs of the $2.2 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 IAC is a more equitable way to recover the costs of the Clean Rivers Project than the volumetric charge (for water used), because the IAC 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 2011 monthly ERU value is $3.45.
  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)ERUERU RateMonthly Cost
    100-600 0.6 $3.45 $2.07
    700-2,000 1.0 $3.45 $3.45
    2,100-3,000 2.4 $3.45 $8.28
    3,100-7,000 3.8 $3.45 $13.11
    7,100-11,000 8.6 $3.45 $29.67
    11,100 and more 13.5 $3.45 $46.58

    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? At this time, there is no credit or incentive program. We are coordinating with the District Department of the Environment (DDOE) to develop an incentive/credit program for the future. Part of the planning process of any future incentive program includes identification of the management practices that will be eligible for credits as well as the timing of the discounts to be put in place. You may want to monitor the DDOE website for any activity/proposals for impervious area credits.
  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


You Rule!  These postings are very helpful. I'm wondering where we are now with this...

Does anyone know if a City's impact fees for connecting to the stormwater utility are discounted if stormwater is managed onsite?  

Is there a price break for a building owner who wants to use green infrastructure to minimize their stormwater contribution to the sewer line?  

Any incentives for using a smaller pipe for lateral tie-in?  

Considering the recent rainfall events along the East Coast and the increasing cost of IAC upon non-profit entities such as cemeteries, it's appropriate to revisit this topic...

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