ADU Rules in Washington, DC — 2026 Guide
Check if your Washington property qualifies for an ADU in 20 seconds
Washington ADU Rules at a Glance
Washington is considered ADU-friendly. Here are the key regulations.
- DC legalized accessory apartments and ADUs in 2016 and expanded rules in 2022.
- ADUs up to 900 sqft allowed by right on qualifying lots.
- Basement conversions are the most common ADU type due to rowhouse density.
- No parking required for ADUs.
What ReadyPermit Checks for Washington Properties
Enter any Washington address and get an instant ADU feasibility analysis covering:
Zoning Compliance
Verify your Washington lot is zoned for ADU construction under current DC and local rules.
Setbacks & Coverage
Check required setbacks, lot coverage limits, and height restrictions for your specific parcel.
ADU Size Limits
Calculate the maximum ADU square footage allowed based on your lot size and primary dwelling.
Permit Requirements
Understand what permits and approvals Washington requires before you can break ground.
Flood & Hazard Zones
Identify if your property falls in a flood zone, fire zone, or other hazard overlay.
Lot & Parcel Data
Pull parcel boundaries, lot dimensions, and existing structures from county records.
Check Your Washington Property Free
Enter your address below. In under 20 seconds you will know if your Washington lot qualifies for an ADU — no phone calls, no waiting.
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