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, URL, and the date Kolmo sourced it; an automated scanner monitors the source pages daily for drift. 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.

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

Everything you need to know about pulling a basement finish 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

Plan-review fee scales with valuation. State surcharge $4.50.

Review timeline

—

When does a basement finish need a permit in City of Mercer Island?

2021 IRC R310: every sleeping room below grade requires emergency escape and rescue opening (egress window). Min sill height 44in, min net clear opening 5.7 sq ft (5.0 grade-floor), min width 20in, height 24in. Ceiling height min 7ft (R305). Entire newly conditioned area must comply with WSEC R402.

Required submittals

floor plan w/ egress windows + ceiling heights
electrical layout
plumbing diagram
mechanical / HVAC plan
WSEC compliance form (newly conditioned space)
smoke/CO alarm locations

Inspection sequence

rough-in (electrical/plumbing/mechanical)
framing
insulation
drywall
final

Contractor specialties needed

general, electrical-01-or-02, plumbing

Notes & caveats

Per Mercer Island Residential Building Permits page (separate "Interior Remodel - Structural" listing): scope is "limited to the interior affecting the structure of a building. I.e. Beams, posts, or lateral resistance." Basement conversion to habitable space typically involves egress windows, framing, and electrical/plumbing — falls under Structural Interior Remodel.

Basement finish permit fee estimate in City of Mercer Island

Worked example for a $40,000 basement finish project (building permit). Your actual fee scales with project valuation.

Building permit fee	$542.75
Plan review	$352.79
WA state surcharge	$4.5
Estimated total	$900.04

Plan-review fee scales with valuation. State surcharge $4.50. Computed from the City of Mercer Island fee bracket schedule · source ↗. Impact/utility fees may apply separately.

How to apply

1. Confirm your parcel's zoning & overlays. Run an address lookup for your City of Mercer Island basement finish — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
2. Assemble submittals (6).
3. Submit through the city portal: Apply via MyBuildingPermit.com. ↗
4. Track review (typical: —). Respond to reviewer comments promptly.
5. Pay issuance fees (Plan-review fee scales with valuation. State surcharge $4.50.) and pick up the permit. Inspection card travels with the job.

Compare this against other cities

Side-by-side basement finish 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.

Basement finish permits in City of Mercer Island — FAQ

When does a basement finish need a permit in City of Mercer Island?

How much does a basement finish permit cost in City of Mercer Island?

For a $40,000 basement finish project, the estimated City of Mercer Island permit fee is about $900.04 — building fee $542.75 + plan review $352.79 + surcharges. Fees scale with project valuation per the city schedule.

City of Mercer Island resourcesPermit portal ↗Fee schedule ↗