Kirkland is one of the best cities on the Eastside for ADU development — large lots, strong rental demand, a faster permit process than Seattle, and a location at the heart of the tech employment corridor. Piper Cole Architects is headquartered in Kirkland and has permitted more ADUs here than anywhere else in our service area.
Kirkland ADU Types and Rules (2026)
- DADU (backyard cottage): Up to 1,000 sq ft, 18 ft max height, 5 ft rear and side setbacks
- Attached ADU: Basement conversion, garage conversion, or addition — no separate size limit beyond overall lot coverage
- Both types: Allowed on one lot simultaneously in most Kirkland residential zones
Kirkland ADU Permit Process
City of Kirkland ADU permits typically process in 4-8 weeks — one of the faster jurisdictions on the Eastside. Kirkland uses an online permit portal. Piper Cole Architects has established relationships with Kirkland permit staff and submits complete, code-compliant packages that minimize correction cycles.
ADU Rental Income in Kirkland (2026)
- Studio ADU: $1,500-$2,000/month
- 1-bedroom ADU: $2,000-$2,700/month
- 2-bedroom ADU: $2,600-$3,400/month
ADU Project Costs in Kirkland
- Garage conversion ADU: $90,000-$175,000
- Detached backyard cottage: $260,000-$450,000
- Architect fees: $15,000-$32,000
Ready to start? See our ADU service or get a free consultation. We are in Kirkland — call 425-753-6452.