Where We Work
We connect homeowners with licensed ADU builders across every King County city — from Seattle's dense neighborhoods to Issaquah's hillside lots, Renton to Redmond. Local knowledge. Real results.
King County Cities We Serve
Every city in King County has its own zoning rules, permit timelines, setback requirements, and fee structures. Our builders know them all — so your project doesn't get delayed by avoidable mistakes.
Seattle has the most active ADU market in Washington State — and the most complex permitting. Seattle's DADU (Detached Accessory Dwelling Unit) program is well-established, allowing backyard cottages on most single-family lots. Seattle also allows a JADU in addition to an ADU, effectively permitting two extra units per property.
Bellevue's ADU regulations were recently updated to align with state law. Bellevue allows detached ADUs on most residential lots and no longer requires owner-occupancy. Bellevue's design review process for larger ADUs adds time, but the city's larger average lot sizes often make detached ADUs well-suited.
Redmond's tech-driven housing demand makes ADU rental income particularly strong. Redmond has updated its ADU code to be among the most permissive in King County — allowing detached ADUs on most single-family lots with straightforward permitting through the City of Redmond.
Kirkland's residential neighborhoods range from flat lakefront lots to steep hillside properties, each with distinct ADU considerations. Kirkland permits detached ADUs and garage conversions citywide. Hillside lots may require geotechnical reports and additional structural engineering.
Renton offers excellent ADU ROI — lower land and construction costs combined with strong rental demand from proximity to Boeing, Amazon, and tech employment centers. Renton's permit process is generally faster and less expensive than Seattle or Bellevue, making it one of the best markets for ADU investment in King County.
Kent's larger average lot sizes make it well-suited for detached ADUs. Kent has updated its zoning code to align with Washington State ADU law, removing owner-occupancy requirements and streamlining the permit process. The combination of affordable construction costs and solid rental demand makes Kent an attractive ADU market.
Issaquah's sloped terrain requires more site-specific planning — many lots benefit from a walkout basement ADU design that takes advantage of grade changes. Issaquah Highlands and other planned communities may have additional HOA rules to navigate. Our builders know the local permit process inside and out.
Sammamish is one of the fastest-growing cities in Washington State, with high demand for rental housing near tech employers. Many Sammamish neighborhoods have HOAs — our builders verify HOA rules before design begins to avoid surprises. The City of Sammamish ADU program is active and builder-friendly.
Burien's affordability and proximity to SeaTac Airport, Amazon, and Seattle make it an increasingly attractive ADU market. Burien permits ADUs on most residential lots and the permit process is generally efficient. Strong rental demand from airport and healthcare workers supports consistent income.
Properties in unincorporated King County (outside any city's jurisdiction) are permitted through King County DPER (Department of Local Services, Permitting Division). Many unincorporated areas have larger lots ideal for detached ADUs. Septic systems, well water, and limited utility infrastructure require extra planning on rural properties.
Local Expertise
King County is not a monolith. Each of its 39 cities operates its own building department with unique rules, timelines, and quirks. A builder who excels in Seattle may not know Redmond's pre-application requirements — or Kirkland's site-specific design standards. Here's why local knowledge drives better outcomes.
Permits
Permit fees, plan review times, design review requirements, and inspector availability all vary by city. An experienced local builder submits complete applications the first time — avoiding the plan review cycles that add months to a project.
Zoning
Setback rules, maximum lot coverage, height limits, and impervious surface limits vary across King County jurisdictions. A design that works in Renton may not comply in Bellevue. Local builders catch these issues before they become costly redesigns.
Utilities
King County is served by dozens of water and sewer districts with different tap fees, capacity charges, and connection requirements. Local builders know which districts have capacity, which charge premium fees, and how to minimize connection costs.
Subcontractors
Experienced King County ADU builders have established relationships with local plumbers, electricians, and inspectors. This means faster scheduling, competitive pricing, and inspectors who are familiar with your builder's work quality.
Quick Answers
Yes — ADUs are permitted across all of King County, including Seattle, Bellevue, Redmond, Kirkland, Renton, Kent, Issaquah, Sammamish, Burien, and unincorporated areas. Each city has its own permit process, size limits, and setback rules. See full eligibility FAQ →
Permit timelines range from 2–4 months in smaller cities (Renton, Kent, Burien) to 4–8 months in Seattle. Bellevue and Kirkland typically fall in the 3–6 month range. Using a pre-approved plan program (where available) can cut permit timelines in half. See full permit FAQ →
Yes. Permit fees alone can range from $3,000 in Renton to $15,000+ in Seattle for the same size project. Labor costs are relatively consistent across the county, but site conditions and utility connection fees vary more. See our full cost guide →
In most King County cities, yes — owner-occupancy requirements have been removed under Washington State law. A few HOA-governed communities may still have restrictions. We verify your property's specific rules as part of our free feasibility review. Full eligibility FAQ →