District of Columbia Statewide Rule

Rainwater Harvesting Rules in Washington, DC

Some RestrictionsApplies statewide across District of Columbia (2026)

Key Facts

Enforcing agency: DOEE
Retention standard: 1.2-inch (90th percentile) storm
Cisterns and rain barrels: SWRv-credited BMP
Harvested water use: Non-potable only
Homeowner program: RiverSmart Homes subsidies

Last verified: July 31, 2026

Summary

Rainwater harvesting is legal and encouraged in the District. DOEE credits cisterns and rain barrels as approved stormwater retention practices, and every major land-disturbing project must retain the 1.2-inch storm on-site under the stormwater rule.

For a site that undergoes a major land-disturbing activity, the property owner shall retain the rainfall from a one and two-tenths (1.2) inch rainfall event, which is the ninetieth (90th) percentile rainfall event for the District of Columbia, measured for a twenty-four (24) hour rainfall event with a seventy-two (72) hour antecedent dry period by: (a) Employing each BMP necessary to retain the one and two-tenths (1.2) inch SWRv requirement...

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Full Breakdown

The District Department of Energy and Environment (DOEE) governs rainwater harvesting as a stormwater best management practice under 21 DCMR Chapter 5. Any major land-disturbing activity must retain the runoff from a 1.2-inch storm, the 90th-percentile rainfall event, on-site, and cisterns and rain barrels earn Stormwater Retention Volume (SWRv) credit toward that requirement. Harvested rainwater is non-potable and limited to irrigation and approved indoor uses under the DC Plumbing Code. For homeowners, no permit is needed for a simple rain barrel; DOEE's RiverSmart Homes program subsidizes barrels and cisterns rather than mandating them.

Violations & Penalties

Development that fails to meet the 1.2-inch retention standard cannot obtain DOEE stormwater plan approval or a certificate of occupancy. Unapproved practices, lapsed maintenance, or potable misuse of harvested water can trigger DOEE enforcement and civil penalties.

Frequently Asked Questions

Is rainwater harvesting legal in Washington, DC?

Yes. The District encourages it and credits cisterns and rain barrels toward stormwater retention. Harvested rainwater is non-potable and limited to irrigation and approved indoor uses under the DC Plumbing Code.

Do I need a permit for a home rain barrel?

No permit is required for a residential rain barrel, and DOEE's RiverSmart Homes program subsidizes them. Larger cisterns tied to development plans are reviewed under DC's stormwater rule.

Sources

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