District of Columbia
For District of Columbia, disclosure required is Yes; sellers of property containing up to four dwelling units must provide a real property disclosure statement including information about radon, asbestos, lead-based paint, and formaldehyde; testing mandated is Yes; D.C. Dept. of General Services must assess D.C.-owned buildings including schools for radon and other IAQ risks; professional certification required is Yes; persons conducting radon screening, testing, or mitigation for a fee must be certified by the National Radon Proficiency Program or the National Radon Safety Board; action level pci l is No D.C.-specific action level; follows EPA recommended 4 pCi/L; school testing required is Yes; D.C.-owned buildings including schools must be assessed for radon, recorded from its source on 2026-08-15.
- jurisdiction
- District of Columbia
- disclosure required
- Yes; sellers of property containing up to four dwelling units must provide a real property disclosure statement including information about radon, asbestos, lead-based paint, and formaldehyde. verified
- testing mandated
- Yes; D.C. Dept. of General Services must assess D.C.-owned buildings including schools for radon and other IAQ risks.
- professional certification required
- Yes; persons conducting radon screening, testing, or mitigation for a fee must be certified by the National Radon Proficiency Program or the National Radon Safety Board.
- action level pci l
- No D.C.-specific action level; follows EPA recommended 4 pCi/L
- school testing required
- Yes; D.C.-owned buildings including schools must be assessed for radon.
- statute citation
- District of Columbia Code §§ 42-1301--1311, 28-4201--4203, 10-712
What the source says
Requires sellers of property containing up to four dwelling units to provide to purchasers a real property disclosure statement on a form approved by the Mayor. Regulation adopting Seller's Disclosure Statement (17 D.C. Mun. Regs. 2708) requires information about sellers' knowledge of environmental problems on the property, including radon, asbestos, lead-based paint, and formaldehyde
— eli.org, retrieved 2026-08-15
Source
- eli.orghttps://www.eli.org/sites/default/files/files-pdf/2025%20Radon.pdf