Which cities is the Kolmo permit lookup verified for?

Ten cities: Seattle, Bellevue, Kirkland, Redmond, Sammamish, Issaquah, Renton, Kent, Federal Way, and Mercer Island. For these, every fee, threshold, and timeline is sourced from the city directly with the exact quote and URL, and re-verified weekly. Outside these ten cities address lookup still works and we render the parcel and Washington-state baseline code, but per-city specifics are flagged as unverified.

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

Address lookup works and parcels resolve to the county building department, but unincorporated coverage is currently baseline-only — Washington-state IRC, IBC, and WSEC plus state critical-area rules. Per-county fee and code deviations have not been verified to the same standard as the ten verified cities.

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 permits in City of Mercer Island: fees, timeline & requirements (2026)

Everything you need to know about pulling a home addition permit in City of Mercer Island, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Apply via MyBuildingPermit.com..

Permit required?

Yes — see threshold below

Permit fee

—

Review timeline

—

When does a home addition need a permit in City of Mercer Island?

Mercer Island distinguishes additions <500sqft (no Intake Screening required) from additions ≥500sqft (Substantial Residential Project, may require Intake Screening prior to review).

Contractor specialties needed

general

Notes & caveats

Per Mercer Island Residential Building Permits page, two addition pathways are listed separately: under "Addition - Less than 500 Square Feet" the page states "If your project meets the criteria, an Intake Screening may not be required." Under "Addition - 500 Square Feet or More" the page states "Considered a Substantial Residential Project: May require an Intake Screening prior to review." Submittal pathways and review timelines differ between the two.

How to apply

1. Confirm your parcel's zoning & overlays. Run an address lookup on the main permits page — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
2. Assemble submittals (site plan, scope-of-work, photos).
3. Submit through the city portal: Apply via MyBuildingPermit.com. ↗
4. Track review (typical: —). Respond to reviewer comments promptly.
5. Pay issuance fees (—) and pick up the permit. Inspection card travels with the job.

Compare this against other cities

Side-by-side home addition requirements across all 10 verified Seattle-area cities.

All City of Mercer Island permits

Every project type — ADU, addition, kitchen, bath, deck, fence, and more — for City of Mercer Island.

City of Mercer Island resourcesPermit portal ↗Fee schedule ↗