Bathroom remodel permits in Mercer Island: fees, timeline & requirements (2026)
Everything you need to know about pulling a bathroom remodel permit in 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 Mercer Island Community Planning & Development.
Free lookup, no account needed — the office that issues the permit at your address, and a layout of the room, cited to Mercer Island's source.
When does a bathroom remodel need a permit in Mercer Island?
Like-for-like fixture replacement in same location with no plumbing rerouting and no new circuits: typically exempt under 2021 IRC R105.2(2)(g). Any relocation, new fixture, new circuit, or shower-pan replacement triggers permits.
How Mercer Island adopted this rule
The threshold comes from the state code (WAC 51.56), which Mercer Island adopts by reference in the provision quoted below.
“The 2021 Edition of the Uniform Plumbing Code (UPC), as adopted and amended by the State Building Code Council in WAC Chapter 51-56, as published by the International Association of Plumbing and Mechanical Officials, is adopted by reference with the following additions, deletions and exceptions. Provided, that Chapter 1, Administration, is not adopted and the Construction Administrative Code, as set forth in Chapter 17.14 MICC, shall be used in place of UPC Chapter 1, Administration. Provided, that Chapters 12 and 14 of the Uniform Plumbing Code are not adopted.”Source ↗verified 2026-04-29
Required submittals
- Floor plan with fixture locations
- Plumbing diagram
- Electrical layout
- Waterproofing detail at tub/shower
Inspection sequence
- Rough-in (electrical/plumbing/mechanical)
- Shower-pan/waterproofing
- Insulation if walls opened
- Drywall
- Final
Contractor specialties needed
General contractor · Plumber
Who can do this work in Mercer Island?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Mercer Island and King County. Kolmo prepares the drawings and submittals, files the bathroom remodel permit with Mercer Island Community Planning & Development, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Mercer Island bathroom remodel quote.
Notes & caveats
The Mercer Island Residential Building Permits page lists "Bathroom remodels, kitchen remodels (without removal of load bearing walls)" under the Non-Structural Interior Remodel pathway. Cross-reference: the multi-jurisdiction tip sheet referenced by Mercer Island marks bathroom/kitchen fixture replacement without plumbing-line modification as exempt for sinks and toilets, but flags that tub/shower replacement requires a permit.
Bathroom remodel permit fee estimate in Mercer Island
Worked example for a $22,000 bathroom remodel project (building permit). Your actual fee scales with project valuation.
| Building permit fee | $583.63 |
| Plan review | $408.54 |
| WA state surcharge | $6.50 |
| Estimated total | $998.67 |
Mercer Island prices a bathroom remodel's building permit on the value of the work: $40.06 up to $500, $118.83 for the first $2,000 plus $23.24 for each $1,000 more up to $25,000, and $671.95 for the first $25,000 plus $16.87 for each $1,000 more up to $50,000. Plan check adds 70% of that fee. Mechanical, electrical and plumbing inspection on the same permit is a combination fee of 31% of the building permit fee (10%, 11% and 10% if permitted separately). The state energy compliance review for a residential alteration is $261 (2026 Fee Schedule). Computed from Mercer Island's adopted fee schedule · source ↗. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.
How to apply yourself
- 1. Check who issues the permit. Run an address lookup for your bathroom remodel in Mercer Island — we'll confirm which office issues the permit at that address, and you can lay out the room.
- 2. Assemble submittals: the 4 documents under Required submittals above.
- 3. Submit through the city portal: Mercer Island Community Planning & Development ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (about $999 for a $22,000 project) and pick up the permit. Inspection card travels with the job.
Or have Kolmo do it
Kolmo prepares the drawings and submittals, files with Mercer Island Community Planning & Development, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Bathroom remodel permits in Mercer Island — FAQ
When does a bathroom remodel need a permit in Mercer Island?
Like-for-like fixture replacement in same location with no plumbing rerouting and no new circuits: typically exempt under 2021 IRC R105.2(2)(g). Any relocation, new fixture, new circuit, or shower-pan replacement triggers permits.
How much does a bathroom remodel permit cost in Mercer Island?
For a $22,000 bathroom remodel project, the estimated Mercer Island permit fee is about $998.67 (building fee $583.63 + plan review $408.54 + surcharges) from Mercer Island's adopted fee schedule. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.