King County is the most populous county in Washington and the thirteenth most populous in the country. Its Permitting Division covers only the unincorporated areas — the rural east, the foothills and the pockets between cities — and on those parcels the permit is split across more agencies than anywhere else in this state.
The Permitting Division provides land use, building, mechanical, fire regulatory and operating permits, code enforcement and a limited number of business licences in unincorporated King County, with most applications filed through the regional online portal.
This guide covers unincorporated King County only. Seattle, Bellevue, Kent, Renton, Federal Way, Auburn, Kirkland, Sammamish, Redmond, Shoreline, Burien and Bothell are incorporated and permit separately — twelve of the cities in this series sit inside this county.
One house, three permitting agencies. Building, land use, mechanical and fire permits come from King County Permitting. Plumbing comes from Seattle–King County Public Health, along with septic, wells and public pools. Electrical comes from the state Labour and Industries programme. Three separate applications, three separate inspection queues, and no single counter that can tell you the status of all of them.
What requires a building permit in King County?
Washington has a mandatory statewide building code. The codes enumerated in chapter 19.27 RCW, the State Building Code Act, are adopted and amended by the State Building Code Council within the Department of Enterprise Services, and they are required in all cities and counties — local government administers and enforces them rather than deciding whether to have them. A city or county may amend the state code, but it amends upward from a floor it cannot opt out of. So the question in King County is not whether a code applies, but which edition is in force and what King County Permitting has added to it.
Permit required
- New buildings, additions, alterations and change of occupancy or use
- Structural alterations, load-bearing changes, foundations, decks and retaining walls
- Plumbing work under the Uniform Plumbing Code as adopted by the state
- Mechanical and HVAC change-outs, fuel gas work and ventilation
- Work affecting the Washington State Energy Code envelope or systems
- Re-roofing above the exempt scope, demolition, and work in critical areas
Often exempt
- Ordinary repairs and maintenance replacing materials in kind
- Small accessory structures below the code threshold, where zoning allows
- Painting, flooring, cabinetry and other finish work
- Like-for-like fixture swaps with no alteration to piping
Local amendments, fee schedules and exempt thresholds differ from one jurisdiction to the next, so an exempt list from a neighbouring city is not reliable. An exemption from a building permit is never an exemption from zoning, critical areas review, the energy code or a trade permit. Confirm scope with King County Permitting before work starts.
Your electrical permit almost certainly does not come from the city. For most of Washington, electrical permits are issued and electrical inspections are carried out by the Electrical Program at the Department of Labour and Industries under chapter 296-46B WAC — not by the local building department. A minority of cities run their own electrical programme instead. Establish which applies to the parcel before you assume a single counter handles everything, because the electrical track runs on its own timetable and its own inspector.
The statewide features that catch projects everywhere
Four things shape a Washington filing more than the model code does. First, the edition is set by the state on a three-year cycle and adopted in two groups over a two-year timeline, so the building, residential, mechanical and plumbing parts do not all arrive on the same day. Second, plumbing runs on the Uniform Plumbing Code as adopted by the state, not the International Plumbing Code that most of the country uses. Third, the Washington State Energy Code is its own code under chapter 19.27A RCW rather than the international energy code, and it is among the most demanding in the country. Fourth, growth management and critical areas regulation reach ordinary residential work near wetlands, steep slopes, streams and shorelines far more often than owners expect. Cascadia subduction zone seismic detailing applies statewide. Rural sites carry a physical step most applicants have never met: most rural and some urban lots need a Critical Areas Designation, and during it you must flag the site — placing flags or tape at key points so county staff can identify the property boundaries and where you intend to build — with the county publishing separate instructions for how the flagging must be done
Who handles permitting in King County?
The Permitting Division issues land use, building, mechanical, fire regulatory and operating permits for unincorporated King County, alongside code enforcement and some business licensing, and publishes turnaround times for residential new construction and for additions and alterations.
| Detail | Information |
|---|---|
| Department | King County Department of Local Services, Permitting Division |
| Address | 35030 SE Douglas Street, Snoqualmie, WA 98065 |
| Phone | (206) 296-6600; code enforcement (206) 296-6680 |
| Hours | Monday to Friday, 8:00 a.m. to 4:30 p.m. |
| Plumbing, septic, wells | Seattle-King County Public Health, separately |
| Electrical | Washington State Department of Labour and Industries |
| Critical areas ordinance | Updated ordinance adopted December 2025, effective February 2026 |
| Applications | Most building and land use permits through the regional online portal |
The critical areas rules were rewritten recently and the change is dated. The King County Council adopted an updated Critical Areas Ordinance in December two thousand twenty-five, and those regulations — excluding ones applying to critical areas inside shoreline jurisdiction — took effect in February two thousand twenty-six. The update expands buffers around certain critical areas in unincorporated King County and clarifies identification and analysis requirements, with the division publishing supporting bulletins through the year.
Infrastructure is rarely the county’s. Fire, water and sewer services in unincorporated areas are usually provided by special districts, and a certificate of availability from the service provider is needed to show whether water or sewer is actually available — being inside a district does not mean the connection exists. Where no service is available, on-site sewage and water well permits must be obtained before applying for the building permit.
Permit types
Residential permits
Most properties in unincorporated King County can support an accessory dwelling unit, with only one allowed per primary detached dwelling or townhouse unit and either the accessory unit or the primary dwelling required to be owner-occupied. Before permitting begins an applicant must file a notice on title and affidavit with the county records office.
How Washington contractor credentials work
Washington registers contractors rather than licensing them. Under chapter 18.27 RCW every contractor must register with the Department of Labour and Industries, file a continuous surety bond — thirty thousand dollars for a general contractor, fifteen thousand for a specialty contractor — and keep liability insurance on file. Registration runs for two years and carries no continuing education requirement at the base level. Crucially, registration is not a competence test and it does not authorise trade work: electrical work requires certification under chapter 19.28 RCW and plumbing under chapter 18.106 RCW, each with its own examination and its own programme office.
A general registration does not let anyone touch the wiring or the pipes. A registered general contractor must subcontract electrical and plumbing work to appropriately certified trades, and an electrical contractor licence additionally requires at least one certified electrician on staff. Verify the registration is active and the bond and insurance current with King County Permitting and with the department, because registration lapses are common and an expired registration invalidates the credential the permit relies on.
Commercial permits
Development on rural land may involve transferable development rights: before receiving a building permit or recording a final plat or short plat, a certificate for the rights being applied must be delivered to the Permitting Division in the applicant’s name, with an extinguishment document following issuance to show the rights have been used and cannot be used again elsewhere.
Registrations, trade certifications and design professionals
Three credential layers appear on Washington projects: the state contractor registration under chapter 18.27 RCW, which nearly everyone doing the work needs; separate state trade certification for electricians and plumbers, each examined and administered by its own programme; and, on commercial and larger residential work, drawings stamped by a Washington-licensed architect or professional engineer. Confirm what King County Permitting requires for the specific building before filing.
King County permit costs and fees
King County publishes turnaround times for residential new construction, additions and alterations alongside its fee schedule. Budget separately for the Public Health plumbing, septic and well permits and for the state electrical permit, since neither is charged by the county.
| Fee component | How it works |
|---|---|
| Building permit | Set by the local jurisdiction, usually on project valuation; the state sets the code, not the fee |
| Plan review | A percentage of the permit fee or a flat charge, set locally |
| Plumbing and mechanical | Separate local permits under the adopted plumbing and mechanical codes |
| Electrical | Usually a state permit fee through the Labour and Industries Electrical Program, not a city fee |
| Energy code | Compliance documentation for the Washington State Energy Code, and review time for it |
| Critical areas and land use | Separate review and fees where wetlands, slopes, streams or shorelines are involved |
Washington sets the code statewide but leaves the fee schedule local, so two jurisdictions on the same edition can price the same project very differently. The electrical fee is the one that most often surprises people, because on most projects it is paid to the state rather than to the city. Ask King County Permitting for the schedule in force on your filing date, and confirm the electrical route separately.
Need a real number for a specific King County project? Send us the scope, address and valuation and we will identify the edition in force, the local amendments, the electrical route and the fee categories that will apply.
Trade permits and who may pull them
Trade permits are separate from the building permit and, in Washington, are not all issued by the same body. Plumbing and mechanical permits come from the local jurisdiction under the codes the state has adopted. Electrical permits come from the Electrical Program at the Department of Labour and Industries, unless this jurisdiction runs its own. That split is the single most common source of confusion on a Washington project.
Your electrical permit almost certainly does not come from the city. For most of Washington, electrical permits are issued and electrical inspections are carried out by the Electrical Program at the Department of Labour and Industries under chapter 296-46B WAC — not by the local building department. A minority of cities run their own electrical programme instead. Establish which applies to the parcel before you assume a single counter handles everything, because the electrical track runs on its own timetable and its own inspector.
- Electrical work follows chapter 19.28 RCW and the state electrical rules at chapter 296-46B WAC, performed by a certified electrician working for a licensed electrical contractor.
- Plumbing work follows the Uniform Plumbing Code as adopted by the state, performed by a plumber certified under chapter 18.106 RCW.
- Mechanical and fuel gas work follows the state mechanical and fuel gas provisions, permitted locally.
Permit required
- Service installations, panel upgrades, new circuits, solar PV and EV chargers
- New plumbing, repipes, water heater change-outs, fixtures, backflow and gas piping
- HVAC installation and change-out, ductwork, venting and commercial kitchen exhaust
- Sprinkler, standpipe and fire alarm work on commercial and multi-family structures
Typically exempt
- Replacing a fixture, switch, receptacle or light with no alteration to wiring or piping
- Clearing a stoppage without replacing or rearranging concealed piping
- Filter, thermostat and routine component service
- Like-for-like appliance repair that does not alter the connection
How to apply for a King County building permit
Twelve of the cities in this series sit inside King County, and each permits its own limits.
County for building and land use, Public Health for plumbing and septic, the state for electrical.
The updated ordinance expanded buffers around certain critical areas with effect from February two thousand twenty-six.
Critical Areas Designation on rural and some urban lots requires physically flagging boundaries and the build location.
Being inside a water or sewer district does not mean service is available at the parcel.
Where no service is available these must be obtained before the building permit application.
Review, corrections and what actually causes delay
In Washington the first cause of delay is the energy code, because the state code is its own instrument and more demanding than the international one most designers default to. After that comes critical areas review, which reaches ordinary residential work near wetlands, streams, steep slopes and shorelines and adds its own study and mitigation timeline. Then the electrical split, where a project waits on a city inspection that was never going to happen because the electrical permit sits with the state. Then edition confusion, because the state adopts in two groups and the parts do not all move together. Build review time into the schedule and confirm the checklist with King County Permitting before filing.
Approvals do not stay live indefinitely. Permit validity periods are set locally on top of the state code, so they differ between neighbouring jurisdictions and cannot be assumed from a previous job. On phased or financed work, confirm the expiry window and keep the permit alive with progress inspections.
Inspections in King County
Where a permit is required, standard checkpoints include footing and foundation, framing, rough-in plumbing and mechanical, insulation and energy code compliance, fire systems on commercial work, and final, with a certificate of occupancy before the building is used. Inspection scheduling is split the same way as permitting: building, fire and land use through the county, electrical through the state programme, and septic, plumbing, wells and public pools through Public Health.
The point to plan around is that the electrical inspections may be booked with a different body entirely. Where the state Electrical Program holds the electrical permit, its inspector attends on the state’s schedule and the local inspector will not sign off electrical work. Sequencing a cover-up around two independent inspection queues is the practical skill on a Washington job.
Do not cover work before the required inspection has been approved. Keep the issued permits — plural — the approved plans and the energy code documentation available on site.
King County permit search and official resources
Permit records in Washington are split the same way the permits are. Where King County Permitting is the authority for unincorporated King County, it holds the building, plumbing and mechanical records — but the electrical record for most projects sits with the state Electrical Program instead. If you are buying, refinancing or renovating, check both, because a clean local record does not mean the electrical work was ever permitted.
Confirm the edition, the local amendments and the electrical route. Washington sets a mandatory statewide minimum under chapter 19.27 RCW, but the edition moves in two groups on a three-year cycle and every jurisdiction may amend upward. All three questions have to be answered for the parcel and the filing date.
These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.
- King County permits
- King County critical areas overview and related permits
- King County permit guide frequently asked questions
- Labour and Industries contractor laws and rules
- Chapter 19.27 RCW, the State Building Code Act
Frequently asked questions
Who issues my plumbing permit in unincorporated King County?
Not the county. Plumbing permits, along with septic, wells and public pools, come from Seattle-King County Public Health, while building, land use, mechanical and fire permits come from King County Permitting and electrical comes from the state programme.
What is site flagging?
A physical marking step in the Critical Areas Designation process. Most rural and some urban lots need a designation, and during it you must place flags or tape at key spots on the property so county staff can identify the boundaries and where you plan to build. The county publishes separate instructions on how to do it.
Have the critical areas rules changed?
Yes, recently. The county council adopted an updated Critical Areas Ordinance in December two thousand twenty-five, effective February two thousand twenty-six for regulations outside shoreline jurisdiction, expanding buffers around certain critical areas and clarifying identification and analysis requirements.
Which code edition applies?
The state edition as amended by the county. Washington has a mandatory statewide building code. The codes enumerated in chapter 19.27 RCW, the State Building Code Act, are adopted and amended by the State Building Code Council within the Department of Enterprise Services and are required in all cities and counties, so local government administers and enforces them rather than choosing whether to have them. The two thousand twenty-one editions took effect on the fifteenth of March, two thousand twenty-four after two delays, and the two thousand twenty-four editions are dated to take effect on the third of May, two thousand twenty-seven. Adoption runs in two groups over a two-year timeline, so the building, residential, mechanical and plumbing parts do not all move on the same day. A city or county may amend upward from the state minimum but cannot opt out of it.
Do I have water and sewer?
Not necessarily, even inside a district. Fire, water and sewer in unincorporated areas are usually provided by special districts, and you need a certificate of availability from the provider. Where no service is available, on-site sewage and water well permits must be obtained before applying for the building permit.
Who registers my contractor?
The state. Washington registers contractors rather than licensing them. Under chapter 18.27 RCW a contractor registers with the Department of Labour and Industries, files a continuous surety bond of thirty thousand dollars as a general contractor or fifteen thousand as a specialty contractor, and keeps liability insurance on file, renewing every two years. Registration is not a competence test and does not authorise trade work: electrical certification comes under chapter 19.28 RCW and plumbing under chapter 18.106 RCW. The electrical permit itself usually comes from the state rather than the city, because the Electrical Program at Labour and Industries issues electrical permits and carries out electrical inspections for most of Washington under chapter 296-46B WAC.
Simplify King County permitting with Alliance Permitting
Three agencies, three queues and a site that has to be physically flagged. Sequencing that is the entire job on a rural King County parcel.
Trusted by leading builders, developers, and national contractors — 22 years of filing in the jurisdictions we write about.
Contractors and builders choose Alliance for King County because the work is done by people who have stood at the counter:
- Twenty-two years of filing, so the edition and the electrical route are settled before submission
- We confirm which state code group governs each part of the work on your filing date
- State contractor registration, bond and insurance verified as active before filing
- Energy code and critical areas documentation prepared rather than discovered in review
- Two inspection queues sequenced so a cover-up never waits on the wrong inspector
Alliance Permitting is a permit documentation and submission company in Washington. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.
Ready to break ground in King County sooner?
Let Alliance prepare, file, and track your King County permits while your crew stays on the job.
More Washington permitting guides
This guide is provided by Alliance Permitting for general information about King County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.