Deck permits in City of Mercer Island: fees, timeline & requirements (2026)
Everything you need to know about pulling a deck 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..
Free lookup, no account needed — your lot polygon, zoning, setbacks and overlays, cited to City of Mercer Island's source.
When does a deck need a permit in City of Mercer Island?
Permit NOT required for sidewalks, decks and driveways constructed under IRC, not more than 30in above grade and not over any basement or story below. Decking replacement on existing decks WITHOUT changing/adding structural members and WITHOUT removing guardrails is also exempt. Per the multi-jurisdiction tip sheet, the 30-inch measurement is taken vertically to the grade below at any point within 36 inches of the outer edge of the deck. Critical-area / flood-hazard exemption rule applies.
How City of Mercer Island adopted this rule
The threshold comes from the state code (WAC 51.51), which City of Mercer Island adopts by reference in the provision quoted below.
“The 2021 Edition of the International Building Code (IBC), including the adoption of ICC/ANSI A117.1-2017, Requirements for Accessible and Useable Buildings and Facilities, as adopted and amended by the State Building Code Council in WAC Chapter 51-50, as published by the International Code Council, excluding Chapter 1, Administration, is adopted by reference, together with the following amendments and additions. The Construction Administrative Code, as set forth in chapter 17.14 MICC, shall be used in place of IBC Chapter 1, Administration.”Source ↗verified 2026-04-29
Required submittals
- site plan with setbacks
- framing plan w/ ledger detail
- footing detail
- guard/handrail detail
Inspection sequence
- footing
- framing
- final
Contractor specialties needed
general
Who can do this work in City of Mercer Island?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout City of Mercer Island and King County. Kolmo prepares the drawings and submittals, files the deck permit with Apply via MyBuildingPermit.com., carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a City of Mercer Island deck quote.
Notes & caveats
From MICC 17.14.010 §105.2: "Sidewalks, decks and driveways constructed under the provisions of the IRC, which are not more than 30 inches (762 mm) above grade and not over any basement or story below" are exempt. Also exempt: "Decking replacement on decks without changing or adding any other structural members or removing guardrails." Critical-area override (per MICC 17.14.010 §105.2): exemptions DO NOT apply in flood-hazard or city land-use critical areas unless work is entirely within or on the exterior envelope of a legally established existing building.
Deck permit fee — Washington baseline, not City of Mercer Island's own schedule
Worked example for a $18,000 deck project (building permit). Your actual fee scales with project valuation.
| Building permit fee | $293.25 |
| Plan review | $190.61 |
| WA state surcharge | $6.5 |
| Estimated total | $490.36 |
Most jurisdictions handle decks as field-inspection or simplified plan review. We have not read City of Mercer Island's adopted fee schedule, so this is not City of Mercer Island's fee: it walks the standard valuation table most Washington cities adopt by reference, as a rough guide. The real numbers are in City of Mercer Island's fee schedule ↗. Impact/utility fees may apply separately.
How to apply yourself
- 1. Confirm your parcel's zoning & overlays. Run an address lookup for your City of Mercer Island deck — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
- 2. Assemble submittals (4).
- 3. Submit through the city portal: Apply via MyBuildingPermit.com. ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (Most jurisdictions handle decks as field-inspection or simplified plan review.) and pick up the permit. Inspection card travels with the job.
Or have Kolmo do it
We pull deck permits in City of Mercer Island every month. We prepare the drawings and submittals, file with Apply via MyBuildingPermit.com., handle reviewer comments, and build the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Deck permits in City of Mercer Island — FAQ
When does a deck need a permit in City of Mercer Island?
Permit NOT required for sidewalks, decks and driveways constructed under IRC, not more than 30in above grade and not over any basement or story below. Decking replacement on existing decks WITHOUT changing/adding structural members and WITHOUT removing guardrails is also exempt. Per the multi-jurisdiction tip sheet, the 30-inch measurement is taken vertically to the grade below at any point within 36 inches of the outer edge of the deck. Critical-area / flood-hazard exemption rule applies.
How much does a deck permit cost in City of Mercer Island?
For a $18,000 deck project, the estimated City of Mercer Island permit fee is about $490.36 — building fee $293.25 + plan review $190.61 + surcharges. Fees scale with project valuation per the city schedule.