Kirkland, WA · KGC
Kirkland ADU Construction
Kirkland's ADU regulations make backyard cottages, carriage houses, and in-law suites increasingly viable. We handle permits, design, and turn-key construction — from the foundation to the final walkthrough.
The Opportunity
Your Backyard Is Generating $0 in Income. It Doesn't Have To.
The average long-term rental rate for a 600–800 sq ft ADU in Kirkland currently runs $2,000–$3,200 per month. A well-designed detached ADU (DADU) costing $200,000 to build can realistically generate $2,500/month in rental income — a 15% gross yield before expenses, in a real estate market where 4–5% cap rates are considered excellent.
But ADUs aren't just about rental income. Kirkland's tech-employed population is increasingly multigenerational. Aging parents who want independence but need proximity. Adult children returning from college who can't afford Kirkland rents. A home office that has its own entrance, its own address, its own bathroom — eliminating the line between work and life.
Kirkland's updated ADU ordinance, amended in 2020 in response to Washington State's housing legislation, significantly simplified ADU permitting and expanded where they're allowed. If you've looked into ADUs in Kirkland before and been discouraged, the rules have materially changed in your favor.
Detached ADUs (DADUs)
A freestanding structure in your backyard — the classic "backyard cottage." Kirkland allows DADUs up to 1,000 sq ft on most single-family lots. They can have full kitchens, separate utility meters, and their own address. Our most popular ADU type.
Attached ADUs
An addition to your primary residence with its own entrance, kitchen, and living space. Common configurations include attached in-law suites, basement apartments with exterior access, and garage conversions with an addition above. Often less expensive than a full DADU.
Garage Conversions
Converting an existing detached garage into living space is often the most cost-effective ADU path. We handle the insulation, plumbing, electrical upgrade, HVAC, egress windows, and interior finish to transform an underused garage into a comfortable, rentable unit.
Carriage House ADUs
For lots with enough depth, a two-story carriage house — garage below, living space above — provides both storage and rental income in a single footprint. Popular in Houghton and Juanita neighborhoods where lots tend to be larger.
Kirkland ADU Rules
What Kirkland's ADU Ordinance Actually Allows
Size Limits
Up to 1,000 sq ft
Kirkland allows DADUs up to 1,000 square feet, or 50% of the primary dwelling's gross floor area — whichever is less. For most Kirkland homes over 2,000 sq ft, this means the full 1,000 sq ft is available. Attached ADUs (AADUs) follow a similar formula.
Owner Occupancy
Not Required
Washington State's 2019 ADU legislation, which Kirkland adopted, eliminated the owner-occupancy requirement for ADUs. You no longer need to live on the property to rent out either the main home or the ADU. This dramatically increases ADU investment flexibility.
Parking
One Space Required
Kirkland requires one off-street parking space for the ADU. This is typically satisfied by an existing driveway or a new parking pad. We incorporate parking into every ADU site plan and confirm compliance before permit submittal.
The Build Timeline
From First Conversation to Certificate of Occupancy
Site Assessment
We review your property's zoning, lot coverage, setbacks, utility locations, and topography. We confirm ADU feasibility and identify any site constraints before design begins. Weeks 1–2.
Design & Permit Drawings
Architectural floor plans, elevations, and site plan. Structural engineering for the foundation and framing. We submit to Kirkland's building department for permit review. Weeks 3–8.
Permit Approval
Kirkland's review process typically takes 6–10 weeks. We respond to any plan check corrections promptly to minimize delays. Utility connection applications are submitted in parallel. Weeks 8–14.
Construction
Foundation, framing, roofing, rough-in, exterior, insulation, drywall, finish work. Final inspection and Certificate of Occupancy. Total construction time: 16–24 weeks. Total project: 6–8 months.
FAQ
ADU Construction Questions
How much does an ADU cost to build in Kirkland?
A turnkey 600–800 sq ft DADU in Kirkland typically costs $180,000–$280,000 including design, permits, and all construction. Attached ADUs and garage conversions typically run $100,000–$180,000 due to lower foundation and exterior costs. We provide a detailed cost breakdown during your initial site assessment.
Can my ADU have a separate utility meter?
Yes. Kirkland and Puget Sound Energy allow separate electrical meters for ADUs. Water and sewer can typically be split through a new service connection — we coordinate with the City of Kirkland for water/sewer connection permits and work with PSE for electrical service. Separate meters simplify tenant billing and protect both parties.
How much rental income can I expect from a Kirkland ADU?
Current rental rates for 600–800 sq ft ADUs in Kirkland neighborhoods like Juanita, Houghton, and Totem Lake range from $1,800–$3,200 per month for long-term tenants. Short-term rental (Airbnb/VRBO) income can be significantly higher, though requires more active management and compliance with Kirkland's short-term rental registration requirements.
Does a DADU affect my property taxes?
Yes — a new DADU will increase your King County assessed value and therefore your property taxes. The increase is proportional to the added square footage and market value. However, rental income from the ADU typically more than covers the additional property tax burden within the first year of operation. We recommend consulting with a CPA familiar with Kirkland investment properties before proceeding.
Get Started
Find Out If Your Kirkland Lot Can Support an ADU
We'll assess your property, confirm zoning feasibility, and outline a realistic path to permit approval and construction. Most Kirkland lots can support some form of ADU — let's find yours.
(425) 555-0198