Accessory Structures in Washington, DC (2026)
9 verified accessory structures rules for Washington, District of Columbia, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
DC allows accessory dwelling units (called 'Accessory Apartments') in most residential zones under 11 DCMR. Detached ADUs have a max footprint of 450 sq ft or 30% of rear yard. Attached ADUs are limited to 35% of the principal residence's gross floor area. Maximum 3 occupants per unit.
Washington DC ADU (Accessory Apartment) Rules
Some RestrictionsADU Permits
Washington DC allows accessory apartments (the District's term for ADUs) by-right in most residential zones (R-1 through R-5) under DC Zoning Regulations Subtitle U § 253. Applicants file a building permit with the Department of Buildings (DOB, formerly DCRA's permitting division). Most R-1 lots can add an internal or detached accessory apartment without zoning relief, though external accessory apartments in R-1 require special exception review by the Board of Zoning Adjustment (BZA).
DC Accessory Apartment Permits (Zoning Subtitle U)
Few RestrictionsADU Impact Fees
Washington DC does not charge traditional development impact fees on residential construction, so accessory apartments are not subject to the impact, school, or transportation fees common in California, Colorado, and many suburban jurisdictions. The principal costs are DOB building-permit fees (scaled to construction value), DC Water meter and account fees if a separate meter is added, and standard utility connection charges. Historic district properties pay HPRB review fees.
DC Accessory Apartment Fees (Permit, Utilities, No Impact Fees)
Few RestrictionsADU Owner Occupancy
Washington DC does not require owner-occupancy as a general condition for accessory apartments under Zoning Subtitle U § 253. The principal dwelling and accessory apartment may both be rented, subject to standard DC rental licensing through the Department of Buildings (DOB) Rental Accommodations Division and the Office of Tax and Revenue Clean Hands certification. This places DC among the more permissive jurisdictions nationally, similar to California after AB 881 (2019).
DC Accessory Apartment Owner-Occupancy (Generally Not Required)
Few RestrictionsADU Rental Restrictions
DC accessory apartments can be rented long-term with a Basic Business License. Short-term rentals (under 31 days) are heavily restricted under the Short-Term Rental Regulation Act of 2018 (D.C. Law 22-307, codified at D.C. Code § 47-2829(j)): STRs are allowed only at the host's primary residence, capped at 90 days per year when the host is not present, and require a separate STR license. An accessory apartment cannot be operated as an Airbnb if the owner does not live in the primary unit, because it is not the host's primary residence.
DC Accessory Apartment Rental Restrictions (Short-Term vs. Long-Term)
Heavy RestrictionsShed Rules
DC exempts a single storage shed up to 10 feet high and 6x8 feet from building permits. Sheds over 50 sq ft are classified as accessory buildings with additional requirements. Sheds may be placed in required rear and side yards under 11 DCMR.
Washington DC Shed Rules & Permits
Few RestrictionsGarage Conversions
Garage conversions in DC require DOB building permits and must comply with 11 DCMR zoning regulations. Converting a garage to habitable space triggers building code requirements including fire sprinklers for new construction, egress, electrical, and plumbing upgrades.
Washington DC Garage Conversion Rules
Some RestrictionsCarport Rules
Washington DC requires a building permit for carports through the Department of Buildings (DOB). Carports are regulated as accessory structures under the DC Zoning Regulations (Title 11 DCMR) and must comply with rear yard, side yard, and lot occupancy limits for the applicable residential zone (R-1 through R-5).
Carport Rules in Washington DC
Some RestrictionsTiny Homes
DC does not recognize tiny homes on wheels as legal dwellings. Permanent tiny homes on foundations must meet full DC Construction Code and zoning minimum lot and setback rules. Accessory dwelling units are allowed as a separate pathway.
Accessory Structures: Tiny Homes
Heavy RestrictionsLooking for District of Columbia county-wide rules?
County ordinances apply to unincorporated areas and may supplement Washington city rules.
Accessory Structures in District of Columbia →