District of Columbia, DC Accessory Structures: Tiny Homes (2026)

DC has one of the most restrictive tiny home landscapes in the country because its zoning predates the movement and no tiny-home overlay exists. A foundation-built tiny home must meet the full 2017 DC Construction Codes as a single-family dwelling, including minimum room dimensions under IRC R304 (habitable rooms at least 70 square feet with a minimum dimension of 7 feet), ceiling height minimums, means of egress, smoke and carbon monoxide alarms, and energy code compliance. IRC Appendix Q (Tiny Houses) has been adopted in DC's 2017 codes, allowing habitable rooms under 70 square feet and ladders to lofts with specific design. Lot size and zoning minimums still apply — most R zones require minimum lot widths of 30-50 feet and lot areas of 2,000-5,000+ square feet, making dedicated tiny-home lots essentially impossible. The ADU pathway under DCMR 11-U 253 allows a tiny-home-size accessory dwelling (up to 35 percent of principal dwelling floor area or 900 sq ft, whichever is less) on many R-1 through R-3 lots. Tiny Homes on Wheels are RVs under DC Code 50-101, subject to RPP parking rules and the 72-hour abandonment limit; permanent residency in a THOW on District land is illegal.