How accurate is the Kolmo permit lookup?

Every fee, threshold, and timeline is sourced from the city or county directly, with the exact quote and URL surfaced on every page. The dataset is re-verified weekly via an automated freshness pipeline. Where a jurisdiction has not published clear guidance, the tool says so rather than guess.

Does the lookup cover unincorporated King, Pierce, or Snohomish County?

Yes. Address-based lookup automatically routes to the county building department when a parcel is outside city limits. King, Pierce, and Snohomish unincorporated jurisdictions are first-class entries in the dataset.

Will this replace calling the permit center?

For most homeowner projects — decks, kitchens, bathrooms, ADUs, fences, siding, windows, flooring, roofing, HVAC, electrical, plumbing — the published answer matches what the permit center will say, and the homeowner can submit with a pre-filled application packet. For variances, conditional uses, or unusual scope, calling the city planner is still recommended.

Where does the address go after submission?

The address is geocoded via Google Maps to identify the correct county, then queried against public county GIS endpoints. Parcel data is cached for 30 days. The address is not contacted, sold, or shared with third parties.

Who built this — and why?

Built by Kolmo Construction, a licensed Seattle-area general contractor. The team works with permit code daily and built this to fix the public web's poor coverage of homeowner permit questions. The lookup is free; if a homeowner wants a contractor for the project, Kolmo is one option.

addition permit requirements across King, Pierce & Snohomish counties

Side-by-side: which 82 cities and counties require a permit for a addition, what triggers one, what it costs, and how long review takes. Verified against each jurisdiction's own page; sources cited per row.

7 of 82 jurisdictions have authoritative rules on file · 7 typically require a permit · 0 often do not.

King County

Jurisdiction	Permit?	Threshold	Fee	Review days	Source
City of Algona city	Pending verification	—	—	—	Portal
City of Auburn city	Pending verification	—	—	—	Portal
City of Bellevue city	Pending verification	—	—	—	Portal
City of Black Diamond city	Pending verification	—	—	—	Portal
City of Burien city	Pending verification	—	—	—	Portal
City of Carnation city	Pending verification	—	—	—	Portal
City of Clyde Hill city	Pending verification	—	—	—	Portal
City of Covington city	Pending verification	—	—	—	Portal
City of Des Moines city	Pending verification	—	—	—	Portal
City of Duvall city	Pending verification	—	—	—	Portal
City of Enumclaw city	Pending verification	—	—	—	Portal
City of Federal Way city	Pending verification	—	—	—	Portal
City of Issaquah city	Pending verification	—	—	—	Portal
City of Kenmore city	Pending verification	—	—	—	Portal
City of Kent city	Pending verification	—	—	—	Portal
City of Kirkland city	Pending verification	—	—	—	Portal
City of Lake Forest Park city	Pending verification	—	—	—	Portal
City of Maple Valley city	Pending verification	—	—	—	Portal
City of Medina city	Pending verification	—	—	—	Portal
City of Mercer Island city	Yes	Mercer Island distinguishes additions <500sqft (no Intake Screening required) from additions ≥500sqft (Substantial Residential Project, may require Intake Screening prior to review).	—	—	Cite verified 2026-04-29
City of Milton (King) city	Pending verification	—	—	—	Portal
City of Newcastle city	Pending verification	—	—	—	Portal
City of Normandy Park city	Pending verification	—	—	—	Portal
City of North Bend city	Pending verification	—	—	—	Portal
City of Pacific city	Pending verification	—	—	—	Portal
City of Redmond city	Pending verification	—	—	—	Portal
City of Renton city	Pending verification	—	—	—	Portal
City of Sammamish city	Pending verification	—	—	—	Portal
City of SeaTac city	Pending verification	—	—	—	Portal
City of Seattle city	Yes	Any additional floor area requires Construction Permit (Addition or Alteration). Plan review required. ECA + lot coverage + setback compliance verified at intake.	Construction Permit (Addition/Alteration). Pay 75% of plan-review + permit fees at application acceptance. See SDCI 2026 Fee Estimator.	—	Cite verified 2026-04-26
City of Shoreline city	Pending verification	—	—	—	Portal
City of Snoqualmie city	Pending verification	—	—	—	Portal
City of Tukwila city	Pending verification	—	—	—	Portal
City of Woodinville city	Pending verification	—	—	—	Portal
King County (unincorporated) county	Yes	—	—	—	Cite verified 2026-04-29
Town of Beaux Arts Village city	Pending verification	—	—	—	Portal
Town of Hunts Point city	Pending verification	—	—	—	Portal
Town of Skykomish city	Pending verification	—	—	—	Portal
Town of Yarrow Point city	Pending verification	—	—	—	Portal
Washington State (baseline) county	Pending verification	—	—	—	Portal

Pierce County

Jurisdiction	Permit?	Threshold	Fee	Review days	Source
City of Bonney Lake city	Pending verification	—	—	—	Portal
City of Buckley city	Pending verification	—	—	—	Portal
City of DuPont city	Pending verification	—	—	—	Portal
City of Edgewood city	Pending verification	—	—	—	Portal
City of Fife city	Pending verification	—	—	—	Portal
City of Fircrest city	Pending verification	—	—	—	Portal
City of Gig Harbor city	Pending verification	—	—	—	Portal
City of Lakewood city	Yes	—	—	—	Cite verified 2026-04-29
City of Milton (Pierce) city	Pending verification	—	—	—	Portal
City of Orting city	Pending verification	—	—	—	Portal
City of Puyallup city	Yes	—	—	—	Cite verified 2026-04-29
City of Roy city	Pending verification	—	—	—	Portal
City of Sumner city	Pending verification	—	—	—	Portal
City of Tacoma city	Yes	Permit required for any addition to an existing building, OR any new accessory structure ≥200 sqft. Alteration/addition <80% of building valuation = Residential Alteration (BLDRA) permit. ≥80% = Residential New Construction (BLDRN) permit (which subsumes site-development review).	—	30–90 days	Cite verified 2026-04-29
City of University Place city	Pending verification	—	—	—	Portal
Pierce County (unincorporated) county	Pending verification	—	—	—	Portal
Town of Carbonado city	Pending verification	—	—	—	Portal
Town of Eatonville city	Pending verification	—	—	—	Portal
Town of Ruston city	Pending verification	—	—	—	Portal
Town of South Prairie city	Pending verification	—	—	—	Portal
Town of Steilacoom city	Pending verification	—	—	—	Portal
Town of Wilkeson city	Pending verification	—	—	—	Portal

Snohomish County

Jurisdiction	Permit?	Threshold	Fee	Review days	Source
City of Arlington city	Pending verification	—	—	—	Portal
City of Bothell city	Pending verification	—	—	—	Portal
City of Brier city	Pending verification	—	—	—	Portal
City of Edmonds city	Pending verification	—	—	—	Portal
City of Everett city	Pending verification	—	—	—	Portal
City of Gold Bar city	Pending verification	—	—	—	Portal
City of Granite Falls city	Pending verification	—	—	—	Portal
City of Lake Stevens city	Pending verification	—	—	—	Portal
City of Lynnwood city	Yes	—	—	—	Cite verified 2026-04-29
City of Marysville city	Pending verification	—	—	—	Portal
City of Mill Creek city	Pending verification	—	—	—	Portal
City of Monroe city	Pending verification	—	—	—	Portal
City of Mukilteo city	Pending verification	—	—	—	Portal
City of Snohomish city	Pending verification	—	—	—	Portal
City of Stanwood city	Pending verification	—	—	—	Portal
City of Sultan city	Pending verification	—	—	—	Portal
Snohomish County (unincorporated) county	Pending verification	—	—	—	Portal
Town of Darrington city	Pending verification	—	—	—	Portal
Town of Index city	Pending verification	—	—	—	Portal
Town of Woodway city	Pending verification	—	—	—	Portal

How this table is built

Each row reflects the most-recently-verified authoritative rule on file for that jurisdiction and project type. “Pending verification” means we have the jurisdiction in our database but haven't yet personally checked the city page for addition rules — those rows fall back to county or WA-state baselines until verified. Sources link directly to the city or county page we read on the verified-on date. See our data-quality leaderboard for how we keep these current.