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May 30, 2026
Kirkland, WA ADU Rules 2026: What You Can Build on Your Lot
Kirkland, WA has updated its ADU ordinance in recent years to align with Washington State’s expanded ADU legislation. Here is a current guide to what you can build, where, and what the process looks like.
ADU Types Allowed in Kirkland
Detached ADU (DADU):
A freestanding structure in the backyard or side yard
Attached ADU:
An addition to the primary home — basement conversion, attached unit, or garage conversion
Both types:
Kirkland allows one of each type per lot in residential zones
Kirkland DADU Size Limits (2026)
Maximum size:
1,000 sq ft
Maximum height:
18 feet in most residential zones
Minimum setbacks:
5 ft rear, 5 ft side in most zones
How Kirkland Differs from Seattle
- Kirkland’s maximum DADU height (18 ft) is lower than Seattle’s (24 ft with pitched roof)
- Kirkland permit review is generally faster than SDCI (4-8 weeks vs. 8-14 weeks)
- Kirkland’s fee schedule differs from Seattle’s — often lower for smaller projects
Kirkland ADU Permit Process
ADUs in Kirkland are permitted through the City of Kirkland’s Planning and Building Department. The process requires a site plan, architectural drawings, structural drawings, and energy calculations. Piper Cole Architects is headquartered in Kirkland and has permitted numerous ADUs with the city. We know the process, the staff, and the common correction points.
See our ADU design service or contact us for a free consultation on your Kirkland ADU. Call 425-753-6452.
Authoritative sources
Regulatory requirements referenced in this guide are set by the official agencies below. Rules change — always confirm current requirements with the source:
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