Plain-English Guide
DC's mold law: what landlords and property managers must do.
The District regulates indoor mold in rental housing with real deadlines and real consequences. Here's the whole framework in plain English — the threshold, the clock, the disclosure rule, and what "done properly" looks like in your file.
The core rule
10 square feet changes everything
In the District, once indoor mold growth in an affected area reaches 10 square feet or more — roughly a 2 ft × 5 ft patch — assessment and remediation must be performed or supervised by a professional licensed by the DC Department of Energy & Environment (DOEE). Below the threshold, an owner may address it themselves following DOEE guidance; at or above it, an unlicensed cleanup doesn't legally close the issue, no matter how clean the wall looks.
Two things make the threshold tricky in practice. Mold routinely extends behind drywall, under flooring, and inside cavities — so what looks like 4 square feet on the surface is often more. And the growth you can see is a symptom: without finding and fixing the moisture source, remediation is temporary. Both are why the law centers on licensed assessment rather than visual guessing.
The landlord's clock
When a tenant gives notice of suspected mold, deadlines start running: the landlord must inspect within 7 days of written notice and remediate within 30 days. Miss the window and you're exposed on multiple fronts — housing-code enforcement (handled by the Department of Buildings), tenant remedies, and a paper trail that reads badly in any later dispute.
The 3-year disclosure rule
Landlords must disclose mold contamination from the past three years to prospective tenants — unless it was remediated by a licensed professional. This is the clause that makes the license on the paperwork worth as much as the work itself: a licensed remediation with clearance documentation ends the disclosure obligation; an unlicensed cleanup leaves it hanging over the unit for three years of leasing cycles.
What "done properly" looks like in your file
A compliant close-out isn't a receipt for "mold removal." It's a licensed assessment with a written scope, containment and remediation performed under the license, correction of the moisture source, post-remediation verification, and a clearance package — the document that satisfies disclosures, boards, buyers, and inspectors. If your vendor can't produce that package, the issue isn't closed.
This page summarizes the District's mold framework for convenience and isn't legal advice — for a specific dispute, talk to a landlord-tenant attorney. For the mold itself, talk to us.
Common questions