Washington ADU permit requirements
Last reviewed: June 22, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Washington, District of Columbia means pulling a building permit from the local authority that issues it. ArchPermit tracks 13 source-cited requirements (9 required, the rest conditional) for this jurisdiction. Submittals go through DOB Permit Wizard → ProjectDox. These requirements were last reviewed June 22, 2026; confirm the exact forms and fees with the local permitting authority.
A source-cited checklist of what an ADU (accessory dwelling unit) permit package needs in Washington. Every item links to its authoritative source; items that vary are flagged to confirm locally.
An accessory apartment is matter-of-right in almost all R (residential house) zones under Zoning Regulations Subtitle U § U253 (subject to its owner-occupancy, minimum-house-size, ≤35%-gross-floor-area, and entrance conditions) — except R-19 and R-20, where it requires BZA special-exception approval; a special exception is also needed to build a NEW accessory building to house the unit. Where the space looks like an independent dwelling but is permitted as part of the principal unit, the Zoning Administrator requires a recorded Declaration of Covenants before the permit issues (ZA-031).
- Architectural Plans / Construction Documentsrequired
Construction documents reviewed for compliance with the building codes and zoning regulations.
source · reviewed 2026-06-22 - Completed Permit Application (DOB Permit Wizard)required
One-/two-family ADU permits are filed in the DOB Permit Wizard; all required fields completed and accurate before submission.
source · reviewed 2026-06-22 - Cover Sheet (DOB template)required
The completed DOB cover sheet; a template and sample are provided.
source · reviewed 2026-06-22 - Estimated Cost of Constructionrequired
The estimated/total construction cost is required at application; the 50% filing fee is based on it.
source · reviewed 2026-06-22 - Floor Plans (existing + proposed)required
Floor plans showing the existing and proposed structures.
source · reviewed 2026-06-22 - Residential Project Checklist (online)required
DOB requires applicants to complete the online residential checklist of minimum plan-review requirements before an application can be submitted.
source · reviewed 2026-06-22 - Signed Construction Contract / Formal Quoterequired
Upload a formal quote, contract agreement, or MS report to pay the filing fee; the remaining balance is based on the signed contract.
source · reviewed 2026-06-22 - Surveyor's Plat (DC-certified)required
Scaled drawing of the lot certified by the DC Surveyor showing lot lines, record dimensions, and existing + proposed structures; required for all exterior work.
source · reviewed 2026-06-22 - Zoning Code Analysis (Subtitle U § U253 compliance)required
For an accessory apartment, the U253 conditions (owner-occupancy, minimum gross floor area by zone, ≤35% GFA, entrance restrictions, occupancy limit) must be met and demonstrated.
source · reviewed 2026-06-22 - BZA Special-Exception Approvalconditional
Required in R-19/R-20 zones and to construct a new accessory building to house the unit; otherwise matter-of-right under U253.
source · reviewed 2026-06-22 - Certificate of Occupancyconditional
Required for Apartment and Two-Family Rental classifications (single-family in R-1A/R-1B/R-2/R-3 is exempt) to legally occupy/rent the new unit.
source · reviewed 2026-06-22 - Declaration of Covenants (recorded)conditional
Where the space has independence + bathroom + cooking characteristics but is permitted as part of the principal unit, a recorded covenant must be furnished to the Office of the Zoning Administrator before permit issuance (ZA-031).
source · reviewed 2026-06-22 - Structural Plans / Engineer of Recordconditionalverify locally
Structural drawings where structural work is involved; basement/below-grade ADU conversions typically trigger this. Confirm the exact engineer threshold on the residential checklist.
source · reviewed 2026-06-22