Short answer: at a value of $750,000, Mercer Island’s building permit fee is $7,499.59, and with plan check and the mechanical, electrical and plumbing combination fee the three lines come to $15,074.17. That is an estimate: the city’s table applied to a value I chose. Other lines come on top.

Piper Cole Architects is based in Kirkland. I design and administer construction, and I do not build. My fixed fee for design and permit is separate from the city’s fees. Every city fee below comes from a City of Mercer Island document I read on October 19, 2026, except the state’s $6.50 fee, which is in RCW 19.27.085. The $750,000 value, the 3,000 square foot house and the 500 square foot addition are my assumptions. The city’s permit FAQ answers “What will my building permit cost?” in two sentences, and I found no building permit estimator or worked example. My permit guide and zoning guide cover the rules, so this page stays on money.

Which documents set the fee

The city’s Permit Fees page links the fee schedule PDF, titled the 2nd Revised 2026 Fee Schedule. That is the document I read. Its Section 8 is labeled “Resolution No. 1698, Effective August 1, 2026” and says it is “otherwise established by Resolution No. 1686.” The July 7, 2026 council minutes show Resolution 1698 passed on the consent agenda, 6 to 0, as agenda bill 6962, to add an affordable housing fee in lieu rate. I found no text saying which resolution set the building permit table, so I credit the schedule, not a resolution, for each number. The December 2, 2025 agenda bill names Resolution 1685 for the 2026 schedule and left the valuation table unescalated. I cannot reconcile 1685 with 1686.

The city’s codes page lists the 2021 building code editions for applications received on or after March 15, 2024. I found no later local ordinance, so confirm the edition for your application date.

How the city values a remodel

The permit fee follows value, and the city defines it. Under MICC 17.14.010, you state the valuation when you apply (section 109.4), and the building official decides it where a resolution does not clearly set it. For a specific scope of work, section 101.4 makes value the fair market value of that work, with time and materials and the contractor’s overhead and profit. A builder’s bid is the natural starting number, and the city checks it against its table.

Appendix A is the city’s table of values per square foot, and says valuations from applicants “will be validated against this table.” Its wood frame dwelling rows run from $213.27 (Good) through $272.51 (Very Good) and $331.75 (Very Good Custom) to $450.23 (Luxury) per square foot. The city’s Fire Area and Valuation Form for alterations has a line for your construction cost, a line for a “Verified Cost” the city fills in, and a line headed “Higher of Verified or Cost.” These are the city’s valuation figures, not my construction ranges. Ask the permit center what it accepts as proof of your bid.

Worked example: a $750,000 remodel

Assumptions: one house, a $750,000 valuation the city accepts, and mechanical, electrical and plumbing work under the building permit. Lines are rounded to the cent:

If the trades are pulled separately, the schedule splits the 31 percent into 10 mechanical, 11 electrical and 10 plumbing. Plan check covers three review rounds; more cost $182 an hour. Other values by the same method:

The bands do not join: the lower band prints $5,448.77 at $500,000.99 and the next starts at $5,547.09; the middle band prints $9,452.10 and the next starts at $9,621.68. I report the table as printed. For scale, Kirkland, Bellevue, Redmond and Seattle fee pages give $11,897.56, $14,919.50, $15,984.90 and $13,885.40 at this value, though each city builds its lines differently, and Kirkland and Seattle include the $6.50 state fee.

Charges outside the building permit line

The schedule says its table covers only the building permit, plan check and combination lines, and that “additional plan review and permit fees may apply.” A whole house remodel can meet these, each only if your lot or scope triggers it.

A sample stack, my assumption: 500 square feet of added footprint (intake screening) and work near trees (arborist review) pays $15,074.17 + $903 + $261 + $182 + $427 = $16,847.17.

Impact fees: none on a remodel

The city’s impact fee page lists what is not assessed, including “Remodeling or reconstruction of existing dwellings” and replacement residences. The code agrees: MICC 19.18.070(B) for parks and 19.19.070(B) for transportation exempt remodeling of existing legally established buildings so long as no additional dwelling unit is created, and the transportation section adds that the use category must not change. A replacement after demolition is exempt only if a complete permit is submitted within 12 months of the demolition.

A new unit costs $4,318.02 transportation plus $6,314.30 parks plus $0 school (the district is not collecting), $10,632.32 on the schedule. Payment is due before the permit issues, unless you defer it up to 18 months with a lien and an $87 review fee. The schedule lists accessory dwelling unit impact fees, while the code says an ADU is not charged a separate fee, so ask in writing before you add one. For where a rebuild begins, see when a remodel counts as a new house.

The 50 percent rule and fire sprinklers

MICC 17.02.020(B) adds section AV107.2 to the residential code. An approved sprinkler system must be installed throughout an existing one- or two-family house undergoing a remodel or addition when the construction value of all additions, alterations or repairs in a 60 month period exceeds 50 percent of the value of the residence, by the fire code official’s method. Between 10 and 50 percent, section AV107.3 requires a household fire alarm if the lot has fire flow, hydrant or access deficiencies.

The city’s Fire Area and Valuation Form shows a method: it prices existing floor area at the Appendix A rates, sets your cost against it and checks a box for under 10 percent, 10 to 49, or 50 percent or greater (a substantial alteration). Suppose, as my assumption, a 3,000 square foot house at the $272.51 Very Good rate, which the form marks “most common.” 3,000 × $272.51 = $817,530. At $750,000, $750,000 ÷ $817,530 is 91.74 percent, so on that assumed house sprinklers would apply, as they would to any remodel above $408,765. Your house will differ: the form also prices garages and covered decks, and the fire code official chooses the method. The sprinkler permit is $1,033; the system is construction cost in your builder’s bid.

When you pay, and how long the permit lasts

• At submittal and issuance. Under section 109.3, plan check is paid when you submit and any balance when the permit issues. The city says no one can pay to expedite. A revision is $360 for a two hour minimum.
• Starting early. Section 109.5 sets a stop work order and a special investigation fee of twice the permit fee, or another amount the building official sets, for work begun without a permit: $14,999.18 on the building permit fee alone.
• Refunds. Section 109.7 lets the building official refund up to 80 percent of a permit fee when no work has been done, on written application within 180 days of the application date.
• Permit life. Section 105.5 expires a permit two years from issuance. The building official may approve one renewal, to three years from the original issue, if the plans do not change, you supply a schedule and management plan, and you ask within 90 days after expiry. The city’s renewal form sets the fee at 50 percent of the building permit fee unless the building official authorizes otherwise, here $7,499.59 × 0.50 = $3,749.80, and takes no scope revisions, though structure or minor interior layout changes are considered case by case.

What I could not confirm

• How a reviewer tests a remodel bid against Appendix A, and whether tree removal fees stack with arborist review.
• Whether the $25 per square foot affordable housing fee in lieu that Resolution 1698 added reaches a single-family project. Its note speaks of hallways and common areas, so I do not price it.
• How the fire code official values the existing house for the 50 percent test. I used the form’s rates; the form prices garages and decks at $43.99 against $44.70 in Appendix A, and its box says 50 percent or greater where the code says exceeds.
• The text of Ordinance 26C-11, why the schedule cites Resolution 1686 where the agenda bill cites 1685, and the ADU impact fee conflict.

City fees, my fee and construction cost

A remodel budget has three lines. The city line leaves out drainage, trees and sprinklers.

Ask whether your builder’s bid includes permit fees. For the wider budget, see planning a million dollar remodel and my Mercer Island remodel page.

Questions