Building Safety in King County, WA (2026)

7 county-level rules, plus city-specific rules for 8 cities in King County, Washington.

Verified from official government sources

Note: These county rules apply to unincorporated areas of King County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Fire Sprinkler Requirements

Unincorporated King County requires automatic fire sprinklers in new IRC-built homes when fire access, floor area, or water supply fall short of set thresholds, with an exception for large rural lots outside the Urban Growth Area.

King County Home Fire Sprinkler Triggers

Some Restrictions

King County Code § 17.04.560

An automatic sprinkler system shall be installed in the habitable space of structures built under the International Residential Code (IRC) when: 1. There is no approved fire access as defined in K.C.C. Title 14 and IFC 503; 2. The structure has a total floor area, including basements, that exceed 10,000 square feet; or: 3. There is not: 3.1 A minimum fire flow of 1,000 gallons per mi...

Full ordinance details →Official source ↗

Childcare Center Rules

Unincorporated King County lets state-licensed family day care homes build to the residential code instead of the commercial code; larger stand-alone child care centers still must meet the full commercial International Building Code.

King County Child Care Building Code Rules

Some Restrictions

King County Code § 16.02.152

The provisions of the International Residential Code apply to the following: The construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses, not more than three stories in height above grade plane with a separate means of egress and their accessory structures, incl...

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Door Locking Hardware

Unincorporated King County requires dwelling entry doors to have a dead bolt lock operable from inside without a key, mounted no higher than 48 inches.

King County Door Locking Hardware Rule

Some Restrictions

King County Code § 16.10.050

16.10.050 Locking hardware. Manually operated edge- or surface-mounted flush bolts shall not be used as a substitute for a dead bolt lock. The lock shall be constructed so that the dead bolt lock shall be opened from the inside without the use of a key or tool and mounted at a height not to exceed 48 inches above the finished floor.

Full ordinance details →Official source ↗

Green Building Code

Unincorporated King County has no mandatory green building code for private construction. Chapter 18.17 requires LEED Platinum or Living Building Challenge certification only for county-owned capital projects and county-financed affordable housing, not homes or businesses built under a standard permit.

King County Green Building Standard Covers County Buildings Only

Few Restrictions

King County Code § 18.17.050.A.3.a

New construction of a LEED-eligible building shall achieve: (1) either LEED platinum certification or the Living Building Challenge certification, or both, if the project is initiated before January 1, 2026; or (2) either LEED Platinum plus Zero Energy or Zero Carbon certification, or Living Building Challenge CORE plus Zero Energy, Energy Petal, or Zero Carbon Certification, if ...

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Building Permits

Unincorporated King County requires a building permit for most interior renovation work; simple finish work like painting, flooring, and cabinets is exempt, and a site plan is waived for alterations that don't change use, add bedrooms, or increase square footage.

King County Interior Renovation Permit

Some Restrictions

King County Code § 16.02.255

A site plan shall not be required for building permits when the scope of work proposed in the permit application is limited to interior alterations and does not result in the following: A. A change in use; B. Additional sleeping quarters or bedrooms; C. Nonconformity with Federal Emergency Management Agency substantial improvement thresholds; or D. An increase in the total square footage or val...

Full ordinance details →Official source ↗

Plumbing Permits

Unincorporated King County adopts the 2018 Uniform Plumbing Code as its plumbing code, requiring a permit for plumbing work; the base permit fee is $132 plus $26 per fixture, and permits expire 18 months after issuance.

King County Plumbing Permit Rules (Unincorporated)

Some Restrictions

King County Code § 16.32.030

Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 16 and 17 and Appendices A (Recommended Rules for Sizing the Water Supply System), B (Explanatory Notes on Combination Waste and Vent Systems), I (Installation Standard for PEX Tubing Systems for Hot- and Cold-Water Distribution) and M (Peak Water Demand Calculator) of the Uniform Plumbing Code, 2018 Edition, as published by or jointly with th...

Full ordinance details →Official source ↗

Building Inspections

Unincorporated King County requires a posted inspection record card on every permitted job, and charges a reinspection fee whenever work isn't ready or corrections weren't completed before the inspector's next visit.

King County Building Inspection Process

Some Restrictions

King County Code § 16.02.450

A reinspection fee may be assessed for each inspection or reinspection when such portion of work for which inspection is called is not complete or when corrections called for are not made. This subsection is not to be interpreted as requiring reinspection fees the first time a job is rejected for failure to comply with the requirements of this code, but as controlling the practice of calling f...

Full ordinance details →Official source ↗