Building Permits in Unincorporated King County: Where to Start

King County's Department of Local Services, through its Permitting Division, issues permits for unincorporated King County. Cities such as Seattle, Bellevue, Renton and Kent issue their own. Mailing addresses do not settle the question: a Renton or Kent mailing address can sit in unincorporated King County.

When you need a permit

King County says a building permit is generally needed to change the occupancy of a building, or to construct, enlarge, alter, repair, move or demolish one. Some common property improvements do not need a building permit, but zoning and critical areas rules still apply.

Permit types

• Single family and duplex: new construction, additions and alterations, detached garages and mechanical systems.

• Commercial and multifamily: new construction, additions and alterations, and tenant improvements.

• Land use: clearing and grading, rezoning, right of way use, land division and tree removal.

• Fire permits: including sprinkler systems and flammable liquid tanks such as propane.

Look up the permit history first

1. Look up the property by address or parcel number.

2. Open the parcel and the Assessor's Report.

3. Click Property Detail.

4. Find the permit history near the bottom of the page. Permits before 1980 are requested by email from King County permit records.

What changes a King County project

• Critical areas. Wetlands, streams, steep slopes and other critical areas are common outside cities and can add studies and a separate review.

• Water and septic. Rural parcels often rely on wells and onsite septic, which need their own approvals before the building permit.

• Clearing and grading. Site work beyond the building footprint can need its own land use permit.

• Rural zoning. Lot size, use and accessory building rules differ from city zoning.

Common questions

Who issues building permits in unincorporated King County?

King County's Department of Local Services, Permitting Division. Incorporated cities issue their own permits.

How do I know if my property is unincorporated?

Do not rely on the mailing address. Check the parcel's jurisdiction in King County's parcel records.

How do I find a King County permit history?

Look up the parcel, open the Assessor's Report, click Property Detail and scroll to the permit history. For permits before 1980, request records by email.

Do critical areas affect a building permit?

Often. Wetlands, streams and steep slopes can require studies and separate review before the building permit moves.

How SASHKOV handles it

• Confirms the jurisdiction, zoning, critical areas and permit history for the parcel.

• Coordinates surveys, critical areas studies, septic and geotechnical work under one SASHKOV contract.

• Prepares the permit set and site plan for King County review.

• Submits, answers corrections and carries the permit through inspection to final.

Where a building requires a licensed architect or engineer of record, SASHKOV brings them into the contract.

Start with a Site Snapshot for the parcel, delivered within 24 hours on business days. For land use questions, see Land Use and Entitlements.

Building in unincorporated King County? Send the address and scope, and SASHKOV will confirm the jurisdiction, permit path and timeline in business days.