Plumbing permits in City of Mercer Island: fees, timeline & requirements (2026)
Everything you need to know about pulling a plumbing 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..
When does a plumbing need a permit in City of Mercer Island?
WAC 51-56 (2021 UPC) requires plumbing permit for installation, replacement, or relocation of any plumbing fixture, water heater, or piping. Like-for-like faucet replacement is exempt.
Required submittals
- fixture count + DFU calc for repipes
- water heater specs
- sewer line plan if site work involved
Inspection sequence
- rough-in / pressure test
- final
Contractor specialties needed
plumbing
Notes & caveats
From multi-jurisdiction tip sheet (Mercer Island): "Bathroom and kitchen fixture replacements without plumbing line modifications such as sinks and toilets" are exempt. However: "Tub and shower replacement does require a permit." Hose bibs and drinking fountains (per the same tip sheet) require a permit. Backflow prevention devices require a permit.
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 (3).
- 3. Submit through the city portal: Apply via MyBuildingPermit.com. ↗
- 4. Track review (typical: —). Respond to reviewer comments promptly.
- 5. Pay issuance fees (Plumbing permit fees by fixture count. Standard residential ~$80-$250.) and pick up the permit. Inspection card travels with the job.
