43% of the District is covered in concrete and asphalt. 50% is owned privately.

For the District to address its stormwater challenge, leaders understood that they needed build stormwater solutions on the public streets and alleys, but also needed to ensure that private properties help as well.

In 2013, after a long process with many stakeholders, the District created a new set of requirements for construction projects to retain stormwater.

DC Stormwater Requirements

Development with 5,000 sq or more of land-disturbing activity

Must retain first 1.2" of rainfall

 
Renovation for which cost exceeds 50% pre-project value of structure and combined footprint of structures & land disturb > 5,000 sf.

Must retain first 0.8" of rainfall

Recognizing that certain sites may face high costs or technical challenges in meeting the requirement, the Department of Energy and the Environment (DOEE) created a Stormwater Retention Credit (SRC) program that provides flexibility for compliance.

The graphic below displays the different options that project stakeholders have for compliance:

A.
Install 100% of retention on the project site

Some examples of acceptable onsite retention include: green roofs, rainwater harvesting systems,, permeable pavement and bioretention.

B.
Retain at least 50% onsite & pay in-lieu fee

In order to meet the regulations you must pay a yearly fee to the District Department of Energy and the Environment for each gallon of offsite retention.

C.
Retain at least 50% onsite & use Stormwater Retention Credits

You can either:
(1). Purchase SRCs on the open market
(2) Produce SRCs on self-owned offsite properties.

An SRC is defined as one gallon of retention for one year. SRCs destined for purchase by developers or building owners can be generated only in the District, in one of two ways:  1) by exceeding the designated retention requirement on a regulated site up to the equivalent of a 1.7-inch storm across the disturbance footprint; or 2) by building a certified stormwater project on a DC property that doesn’t otherwise have a retention requirement.

District’s SRC program has great potential to reduce the harmful effects of contaminated water streaming from impervious surfaces, and thereby accelerate the restoration of the Anacostia River. However, not all stormwater runoff is equal. Stormwater from especially dirty impervious surfaces, or stormwater that rushes into especially small streams, is extremely damaging. There needs to be a way to focus on that: the biggest bang for the buck. That’s RainPay.

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