King County, WA
King County plumbing permit cost
A plumbing permit in unincorporated King County is issued by Public Health — Seattle & King County
and the schedule is short: $137.00 for the permit plus $27.00 for each fixture. One fixture is $164.00, a water heater with two other fixtures is $218.00, and a gas piping permit uses the same arithmetic with outlets in place of fixtures. An Already Built Construction permit, for work done without one, is $273.00 plus $55.00 per fixture.
How this fee is calculated
These are the components the schedule defines for this permit, as they applied on 2026-09-28. A component only applies to your project if its conditions match — read that column before assuming a figure. Want a figure for your own project? Estimate this fee with the permit fee calculator.
| Component | Formula | Applies when | Range |
|---|---|---|---|
| Already Built Construction permit, $273.00 plus $55.00 per fixturePermit fee | $273.00 plus $55.00 per fixture | permit kind is already built | — |
| Plumbing or backflow permit, $137.00 plus $27.00 per fixturePermit fee | $137.00 plus $27.00 per fixture | permit kind is not provided | — |
| Re-inspectionPermit fee | $137.00 flat fee | reinspection is true | — |
A real permit fee is these components added together. The department’s final calculation is the one that applies — this is the schedule it will be based on.
A worked example
Follow the arithmetic by hand. Every line is produced by the engine from the rules above, so the total cannot drift away from the schedule behind it.
Worked example
A water heater replacement plus two other plumbing fixtures in a single-family home in unincorporated King County, filed as one plumbing permit.
| Input | Value |
|---|---|
| Fixtures | 3 |
Example total
$218.00
An estimate, not an official fee. It is calculated from the published fee schedule as it applied on 2026-09-28. The permit office’s own calculation is the one that applies, and your project may fall under rules this schedule does not describe.
Fee schedule as of 2026-09-28Rules applied 1Rules considered 3
| Component | How it is calculated | Amount |
|---|---|---|
Plumbing or backflow permit, $137.00 plus $27.00 per fixturePermit feePlumbing and Gas Piping Program fees: "Plumbing/Backflow Permit — $137 plus $27 per Fixture", effective January 1, 2026. The $137 is a base charge rather than a first fixture, which is why the allowance is zero and a one-fixture permit pays $164.00.Show the working
| $137.00 plus $27.00 per fixture | $218.00 |
| Total | $218.00 |
Fees that do not apply here
Listed so you can see what was considered and left out, rather than wondering whether something is missing. A rule can also be left out because it is not published for this permit at all, and that is stated where it matters.
- Already Built Construction permit, $273.00 plus $55.00 per fixture — This fee does not apply to the inputs provided.
- Re-inspection — This fee does not apply to the inputs provided.
Assumptions
- Calculated from 1 fee rule in effect on 2026-09-28.
- Amounts are rounded to the nearest cent, once, at the end of each component.
Three fixtures at $27.00 is $81.00, and the permit's $137.00 base is added to that rather than covering the first fixture, so the total is $218.00. A one-fixture permit is $164.00, not $137.00 — the base is a charge, not an allowance. If the same work had been done before a permit was taken out, the Already Built Construction row would apply instead at $273.00 plus $55.00 per fixture, which for three fixtures is $438.00, with any permit fees already paid deducted from it.
What is different in King County
The plumbing answer here is the shortest schedule in this dataset and one of the most misread, because of a single question: is the $137.00 a base charge or the first fixture? It is a base charge. The schedule's row reads "Plumbing/Backflow Permit — $137 plus $27 per Fixture", the base has no allowance attached to it, and a one-fixture permit therefore costs $164.00 rather than $137.00. The same reading applies to gas piping, where the row is $137.00 plus $27.00 per outlet.
There are two other permit rows on the same page. The Already Built Construction permit, for work "done without having paid any permit fees", is $273.00 plus $55.00 per fixture or outlet, with the schedule's own note that fees already paid are subtracted from the total. A re-inspection is $137.00 — a charge for a second visit rather than part of the permit.
The page also prices the things around the permit rather than the permit itself: plan review at $273.00 per hour, an inspection outside regular hours at $410.00 per hour, a requested site visit where no permit exists at $273.00, a permit renewal at $68.00, and an administrative fee of $41.00 for a permit modification, a correction or refund processing. Re-pipe projects carry a supplemental fee based on the number of anticipated inspections multiplied by the program's hourly operating rate, calculated on a worksheet the program publishes.
Two things make this jurisdiction different from the other jurisdictions' plumbing pages. The first is who issues it: the county's permitting division prices building work, and this permit comes from a health department with its own schedule, its own effective date and its own hourly rates. The second is that the same schedule also prices Seattle's plumbing permits, because Seattle's own fee subtitle sends them to the same program — so the two jurisdictions' plumbing pages quote the same document, which is the only instance of that in this dataset.
What this page cannot do is price a plumbing job that is part of a larger building project. Denver prices a plumbing permit from the value of the plumbing work; Westminster adds 15% of the building permit fee; King County's health department charges per fixture and would charge plan review by the hour where plans are submitted, which is a different question from "how much is the permit". The per-fixture answer is the published one and it is the one shown here.
What this figure does not include
Impact fees, utility connections and other departments’ permits are the usual omissions, and in some jurisdictions they are larger than the permit fee itself.
Not included in these figures
This estimate is the Plumbing and Gas Piping Program's permit fee for the fixtures or outlets entered. It excludes:
- Plan review, which this program charges at $273.00 per hour rather than as a percentage, and which is not part of the permit fee.
- The $137.00 re-inspection, the $68.00 permit renewal, the $41.00 administrative fee for a modification, correction or refund, the $273.00 site visit where no permit exists, and $410.00 per hour for an inspection outside regular hours.
- The re-pipe supplemental fee, which the schedule calculates from the number of anticipated inspections times the program's hourly operating rate, on a worksheet it publishes.
- Gas piping work priced per outlet, which uses the same $137.00 plus $27.00 arithmetic as fixtures but is a separate permit row: $27.00 per outlet rather than per fixture.
- The Already Built Construction premium unless it is selected: that permit is $273.00 plus $55.00 per fixture, for work done without a permit, with fees already paid deducted from the total.
- Anything charged by the county's Permitting Division — the building permit, its two valuation tables, the state building code surcharge, and any mechanical work, which are separate permits from this one.
- Sewer and water connection charges, which are utility charges rather than permit fees, and on-site septic design and installation, which the same health department reviews under a different program.
- The cost of the fixtures and their installation, which is the work itself rather than the permit.
What you need before applying
- The plumbing permit comes from the health departmentRequired
Guide 02: "On-site septic design and installation, plumbing, and gas-piping permits are issued by Seattle-King County Public Health." The program's schedule charges $137.00 plus $27.00 per fixture, and the $137.00 is a base charge rather than a first fixture — one fixture costs $164.00, not $137.00.
Common questions
How much is a plumbing permit in King County?
$137.00 plus $27.00 per fixture. Three fixtures is $218.00; one fixture is $164.00, because the $137.00 is a base charge rather than a first fixture. A gas piping permit uses the same base with $27.00 per outlet instead of per fixture.
Who issues a plumbing permit in unincorporated King County?
Public Health — Seattle & King County, through its Plumbing and Gas Piping Program, not the county's Permitting Division. The county's own fee guide says so: "On-site septic design and installation, plumbing, and gas-piping permits are issued by Seattle-King County Public Health." The program's schedule is dated effective January 1, 2026.
Is plan review included in the fixture fee?
No. Plan review is charged at $273.00 per hour by this program, separately from the permit, and the schedule lists it as its own row for both plumbing/backflow and gas piping. The per-fixture figure on this page is the permit fee only.
What if the work was already done without a permit?
The Already Built Construction permit applies: $273.00 plus $55.00 per fixture or outlet, for work "done without having paid any permit fees". The schedule's own note says fees already paid are subtracted from that total. Three fixtures would be $438.00.
How much is a re-inspection?
$137.00, charged when a second visit is needed. The same page also prices an inspection outside regular hours at $410.00 per hour, a requested site visit where no permit exists at $273.00, a permit renewal at $68.00, and an administrative fee of $41.00 for a permit modification, a correction or refund processing.
Is this the same fee Seattle charges?
Yes — the same document. Seattle's fee subtitle, at SMC 22.900G.030, directs plumbing, medical gas and fuel gas piping fees to "the Director of King County Public Health", so a plumbing permit in Seattle is priced by this county program rather than by the City. It is the only schedule in this dataset that prices permits in two jurisdictions.
Source and verification
The documents behind every figure on this page, with the dates that make them checkable.
- Fee schedule (PDF)CountyPrimary source
Plumbing and Gas Piping Program service fees (effective January 1, 2026)
A county document that prices City permits, which is why it is recorded against Seattle as well as against King County. SMC 22.900G.030 is the City's own instruction: "Fees for plumbing, medical or dental gas, lab gas, and fuel gas piping shall be collected by the Director of King County Public Health in accordance with the fee schedule as set forth in Seattle Municipal Code Section 504." The figures are $137.00 plus $27.00 per fixture. The same PDF appears in the King County payload under the same key, because it is the same document and the same fee.
Verification
Last verified against the official source in Sep 2026.