Basement finish permit requirements across 16 Seattle-area cities
Side-by-side: which of Seattle, Bellevue, Kirkland, Redmond, Sammamish, Issaquah, Renton, Kent, Federal Way, Mercer Island, Shoreline, Tacoma, Lakewood, Puyallup, Everett, Lynnwood require a permit for a basement finish, and what triggers one — each row quoted from the city's own code or permit page, with the source linked. Fees and review times appear where the city publishes them.
12 of 16 cities have authoritative rules on file · 16 always require a permit · 0 depend on the scope · 0 do not.
King County
| Jurisdiction | Permit? | Threshold | Fee | Review days | Source |
|---|---|---|---|---|---|
city | Always | Finishing or altering a basement is an alteration of the building and needs a permit. 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. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://mybuildingpermit.com. | 14–30 days | Cite verified 2026-05-17 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. Finishing or converting a basement into habitable space is a remodel requiring a building permit; hard-wired smoke detectors must be shown on each floor including basements. | Plan-review fee scales with valuation. State surcharge $6.50. | — | Cite verified 2026-05-29 |
city | Always | Finishing or altering a basement is an alteration of the building and needs a permit. Finishing or remodeling a basement is processed under the Single-Family Interior Remodel permit; no basement-specific square-footage exemption is published. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-29 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. Finishing a basement changes the living space and requires a residential building permit; submit a fully dimensioned floor plan for each floor including basements. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-29 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. Finishing/converting a basement into habitable space is an alteration/change-of-use and requires a building permit (egress, framing, electrical, mechanical). No Kirkland basement-specific exemption is published. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-10-18 |
city | Always | Finishing or altering a basement is an alteration of the building and needs a permit. 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. | Plan-review fee scales with valuation. State surcharge $6.50. | — | Cite verified 2026-04-29 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. 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. | Plan-review fee scales with valuation. State surcharge $6.50. Apply through the Redmond ePermitting Service, REPS (https://cityofredmondwa-energovweb.tylerhost.net/apps/selfservice); plan-reviewed permits go through Plan Review Online, and the How to Apply page (https://www.redmond.gov/462/How-to-Apply) says which. | — | Cite verified 2026-10-02 |
city | Always | Finishing or altering a basement is an alteration of the building and needs a permit. 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. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://permitting.rentonwa.gov. | — | Cite verified 2026-05-17 |
city | Always | Finishing or altering a basement is an alteration of the building and needs a permit. 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. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-10-02 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. Adding habitable rooms requires Construction Permit. Egress window required for any sleeping room (2021 IRC R310). Ceiling-height minimums and emergency-escape openings are common rejection reasons. | — | — | Cite verified 2026-04-26 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. 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. | — | — | Cite verified 2026-05-17 |
Pierce County
| Jurisdiction | Permit? | Threshold | Fee | Review days | Source |
|---|---|---|---|---|---|
city | Always | Finishing or altering a basement needs a building permit. 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. | Plan-review fee scales with valuation. State surcharge $6.50. Apply through Lakewood's Online Permit Center (https://app.oncamino.com/lakewood_wa), linked with the account steps from the city's Apply for a Permit page (https://cityoflakewood.us/permit-center/). | — | Cite verified 2026-04-29 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. 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. | Plan-review fee scales with valuation. State surcharge $6.50. Apply through Puyallup's online permit system, CityView (https://permits.puyallupwa.gov/Portal); the Permit Services page (https://www.puyallupwa.gov/325/Permit-Services) walks through the steps and fees. | — | Cite verified 2026-04-29 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. 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. | Plan-review fee scales with valuation. State surcharge $6.50. | 14–30 days | Cite verified 2026-04-29 |
Snohomish County
| Jurisdiction | Permit? | Threshold | Fee | Review days | Source |
|---|---|---|---|---|---|
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. 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. | Plan-review fee scales with valuation. State surcharge $6.50. | 14–30 days | Cite verified 2026-10-02 |
city | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. 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. | Plan-review fee scales with valuation. State surcharge $6.50. | — | Cite verified 2026-10-02 |
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 basement finish 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.