Do You Need a Permit? How to Check a Washington Renovation Project
No state office answers this for your address. Washington adopts the building codes, then hands each city and county the job of amending, enforcing and permitting them, so the answer belongs to the jurisdiction that contains the parcel — and it can differ on either side of a city limit. Replacing the roofing on a one- or two-family house needs no permit in unincorporated King County; a reroof needs a permit inside the city of Snoqualmie. Both are stated on those jurisdictions’ own permit pages, and Snoqualmie’s page sends unincorporated King County properties to the county instead.
Three questions decide a project, and they are worth asking in this order:
- Which jurisdiction contains the parcel?
- What does the work actually change?
- What does that jurisdiction require for that scope?
What the state decides, and what it leaves to your city or county
Washington has one state building code and many local versions of it. RCW 19.27.031 adopts the model codes by reference — the International Building Code, the International Residential Code, the mechanical, fire and plumbing codes among them — and sets a three-year adoption cycle that follows the model codes’ own cycle. The same chapter then moves the work to the local level: RCW 19.27.050 makes counties and cities responsible for enforcing the code, and provides that a county or city without a building department must contract another agency to enforce it.
RCW 19.27.040 and RCW 19.27.060 let each governing body amend the codes inside its jurisdiction, so long as the amendments do not fall below the state’s minimum performance standards, and an amendment affecting single-family or multifamily dwellings does not take effect until the state building code council approves it under RCW 19.27.074(1)(b). RCW 19.27.090 reserves land use and zoning, building setbacks, site development, snow loads, wind loads and local fire zones to local jurisdictions outright.
The council’s site describes the 2021 editions as taking effect on 15 March 2024 and sets the effective date of the 2024 editions at 3 May 2027, while its codes page still carries 2018 language in places — so read the date rather than the edition number, and ask which edition the department enforces. The council also says where the adopted model code can be read without buying it: at “the permit counter of your local building department.”
The exemption list is real, and it is local
Read two jurisdictions’ permit pages against each other and the pattern is clear: each publishes the work that needs a permit and the work that does not, and the two lists do not agree.
King County’s page is written for unincorporated King County. It requires a building permit to change a building’s occupancy, or to construct, enlarge, alter, repair, move or demolish one, and then states that, unless the property contains critical areas, no permit is needed for a shed of 200 square feet or less, fences 6 feet high or less, most retaining walls 4 feet high or less, replacement of roofing or siding on detached one- and two-family houses, or roof-mounted solar panels under 4 pounds per square foot.
Snoqualmie’s page draws several of the same lines at different numbers — a shed exemption that stops at 120 square feet, a permit for a reroof, a permit for fences over 6 feet — and adds the rest of its own list: mechanical appliances, plumbing fixtures where water lines, drains or vents are installed or modified, fire sprinkler and alarm work, demolition, and any development in the floodplain. Both pages exempt interior finish work and installing or replacing siding.
| The work | Unincorporated King County | City of Snoqualmie |
|---|---|---|
| A storage shed, as an accessory to a house | No permit at 200 square feet or less | No permit at 120 square feet or less |
| A fence | No permit at 6 feet or less | No permit under 6 feet |
| An uncovered deck | No permit at 30 inches or less above the ground | No permit at 30 inches or less above grade |
| Re-roofing a one- or two-family house | No permit — roofing replacement is on the exempt list | A permit is required for a reroof |
| Interior finish work | No permit | No permit |
| A furnace or heat pump | Mechanical permit required | Permit required |
The rows that match matter as much as the row that does not: the differences concentrate in the decisions that turn on a number — square feet, height above grade, whether a structure is attached.
Exempt from a permit is not exempt from the rules
Two qualifications sit behind the lists, and both come from the jurisdictions’ own wording.
King County’s exemptions apply “unless your property contains critical areas,” and the same page names what can require a permit whatever the work is: critical areas, established clearing limits, flood zones, historically sensitive areas, setback areas, shorelines, steep slopes, total impervious lot coverage and wetlands. That county also requires a land use, clearing and grading permit for grading within a critical area, excavation greater than 5 feet deep or 100 cubic yards, fill greater than 3 feet deep or 100 cubic yards, or more than 2,000 square feet of new impervious surface. A patio or a widened driveway is where a homeowner meets that last one.
The shoreline rule states the principle most plainly: shoreline master program regulations “generally apply whether or not a shoreline permit is required.” A substantial development permit covers most development above a dollar threshold that has stood at $8,504 since 1 July 2022, and the local government issues it and files it with Ecology.
Nor does the code switch off where no permit is required: the lists say no application is required, not that the work is unregulated. Zoning, setbacks and site development are reserved to the local jurisdiction by statute, and a structure that breaks them breaks them whether or not it needed a permit to be built.
The permits that run alongside the building permit
A building permit is one of several, and they do not all come from the same office.
Electrical. The Department of Labor & Industries states that electrical work in Washington requires a permit and inspection, with a few exceptions (chapter 296-46B-901 WAC covers them). Whoever does the work buys the permit: an electrical contractor must purchase their own for work on your property, and a homeowner may buy one only for work they are doing themselves. The jurisdiction is a separate map from the building permit’s — a city that does its own electrical permits and inspections, or Tacoma Power’s service area, issues them, and every other jobsite in Washington is permitted and inspected by L&I. A permit is valid for only one specific job site address, apart from annual permits and two-family dwellings, and two or more entities may never work under the same permit. The inspection must be requested before anything is buried or concealed and within three days of completing the installation or one day of energizing it.
Septic systems. The Department of Health divides on-site sewage regulation by design flow: the local health officer approves systems up to 3,499 gallons per day, the department’s large on-site sewage system program covers 3,500 to 100,000, and Ecology takes larger and industrial systems. A septic repair or expansion is a health jurisdiction permit, not a building department one.
Stormwater during construction. Ecology’s Construction Stormwater General Permit is required when a project disturbs land and either disturbs an acre or more, is part of a larger common plan that will disturb an acre or more, or is of any size and is judged a significant contributor of pollutants — and where stormwater could run off the site or enter a conveyance to surface waters, which the agency says is almost every case. A Stormwater Pollution Prevention Plan is required from the first soil disturbance until the site is stabilized.
Ecology’s guidance is that projects “must always comply with the local government’s regulations, including any requirement to obtain a local permit, such as a building permit or a clearing and grading permit,” and that the thresholds at which those local requirements apply “will vary across local jurisdictions.”
How to check, in order
- Find the jurisdiction that contains the parcel. City limits, not mailing addresses, draw the line, and the building department will confirm which one covers an address.
- Describe the work as changes, not as a project. Say what is added, moved, removed or newly connected: square feet of new structure, height above grade, whether a deck is attached to the house or serves the required exit door, whether a drain or a vent is modified, whether a circuit is new.
- Ask the permit counter four questions. Does this scope need a building permit? Which separate electrical, plumbing and mechanical permits come with it, and who issues each one? Does this parcel carry critical area, floodplain, shoreline, setback or lot-coverage conditions that change the answer? Which code edition and fee schedule applies?
- Write the answers down, with the date and the name of the person who gave them.
- Expect the permit to carry the project’s particulars. For construction costing more than $5,000 the application must include the parcel number or legal description and street address, the owner’s name, address and phone number, and the prime contractor’s business name, address, phone number and current state contractor registration number. That information is printed on the permit and on the inspection record card posted at the site, and the application is kept on record for anyone who asks. A copy of any permit over $500 goes to the county assessor.
Where the paperwork stops
A permit authorizes work and sets inspection points; it does not make the work correct, and it does not move the risk in a structural change, a gas appliance, a service panel or a septic system to the department that issued it. Those belong to a registered contractor and, in the licensed trades, to a certified individual. If a bidder proposes to work without the permit the address requires, or asks you to take out the permit for work they will perform, check who you are dealing with before you compare prices.
Start with the address rather than the project: find the jurisdiction, describe the change, and ask the four questions before the first bid is written. The renovation-planning guide shows how the answers feed scope, sequence and budget; verifying a contractor covers the record behind the registration number that goes on the application; and comparing quotes covers what a bid should say about permits and fees.