Washington · Penalties if you skip one

What you can build without a permit in Washington

By Mario Bailey Last checked · 58 official sources

Quick answer

Across the 8 Washington jurisdictions we have verified, 4 of 80 project rules need no permit at all, 48 turn on a size or scope condition the jurisdiction publishes, and 28 require a permit regardless. Deck work is where the answer most often comes with a published condition rather than a flat yes: 8 of the 8 jurisdictions that answer publish one. The numbers are not statewide: deck thresholds alone run from 18 to 30 inches depending on the jurisdiction.

How to read this page

"No permit" means the jurisdiction publishes that the work needs no building permit. "Depends" means it publishes a size, height, depth, cost or scope condition that decides the answer, quoted in its own words in the last column; the number beside it is the figure that condition turns on, and which side of the number is exempt is stated by the condition, not by us. Exempt from a building permit is not exempt from zoning, setbacks, height limits, flood rules, an HOA, or a separate electrical, plumbing or mechanical permit, and several of the conditions below say exactly that.

Deck

All 8 make the deck answer turn on a size or scope condition the jurisdiction publishes, and the 7 that state a number publish figures from 18 to 30 inches.

Jurisdiction Permit Published figure What the rule says
Bellevue Depends 30 inches decks where the highest walking surface is 30 inches or less above grade do not require a permit; decks over 30 inches above grade require a permit with plan review.
Clark County Depends 30 inches Exempt only if the deck does not exceed 200 square feet, is not more than 30 inches above grade at any point, is not attached to a dwelling, does not serve a required exit door, and is not used for a hot tub or pool; all other decks require a permit.
King County Depends 30 inches uncovered decks 30 inches or less above ground do not require a building permit in unincorporated King County; decks over 30 inches above grade require a permit.
Pierce County Depends 30 inches Decks not more than 30 inches above grade at any point, and not over any story or basement below, are exempt; Pierce County code sets no separate floor area cap for decks; taller decks, or decks over a story or basement, require a building permit.
Seattle Depends 18 inches decks more than 18 inches above grade require a permit; decks 18 inches or less above grade and not over a basement do not require a permit.
Snohomish County Depends 30 inches uncovered decks, deck steps, and uncovered porches for residential buildings exempt if 30 inches or less above adjacent grade at any point, not over a basement or story below, and not part of a required accessible route; covered or taller decks require a permit.
Tacoma Depends 200 sq ft freestanding decks not exceeding 200 sq ft and not more than 30 inches above grade are exempt; decks over 200 sq ft, over 30 inches above grade, or attached to the dwelling require a permit.
Thurston County Depends 30 inches Decks are exempt if the surface is 30 inches or less from the ground to the top of the deck.

Fence

All 8 make the fence answer turn on a size or scope condition the jurisdiction publishes, and the 8 that state a number publish figures from 6 to 8 feet.

Jurisdiction Permit Published figure What the rule says
Bellevue Depends 8 feet fences over 8 feet in height require a building permit; fences 8 feet or under do not require a permit.
Clark County Depends 7 feet Fences seven feet or less in height do not require a permit; fences over 7 feet in height require a Fence/Retaining Wall (FRT) permit.
King County Depends 6 feet fences 6 feet or less do not require a building permit in unincorporated King County; fences over 6 feet require a permit.
Pierce County Depends 6 feet Fences 6 feet or less in height, measured from grade, are exempt; taller fences require a building permit.
Seattle Depends 8 feet fences under 8 feet with no masonry or concrete elements exceeding 6 feet do not require a permit.
Snohomish County Depends 8 feet fences 8 feet or less in height exempt, provided they have no masonry or concrete elements above 6 feet (wire strands atop an 8-foot fence are excluded from the height measurement); taller fences, or fences with masonry/concrete above 6 feet, require a permit.
Tacoma Depends 7 feet fences 7 feet or under in height do not require a building permit; fences over 7 feet require a permit.
Thurston County Depends 8 feet Fences 8 feet tall or shorter are exempt from a county building permit.

Patio

Bellevue and Seattle require no patio permit at all. 6 of 8 make the patio answer turn on a size or scope condition the jurisdiction publishes, and the 2 that state a number all publish 30 inches.

Jurisdiction Permit Published figure What the rule says
Bellevue No permit On-grade patio installation and repair does not require a building permit in Bellevue per the city's work-requiring-permits FAQ. Projects involving significant earthwork, grading, or lot changes may have separate requirements.
Seattle No permit Patio slabs and concrete flatwork installed on grade do not require a building permit in Seattle per the SDCI do-you-need-a-permit guidance.
Clark County Depends Patio and concrete slabs on the ground grade are exempt from permit but may not be built on easements; adding a patio cover or enclosing a covered patio requires a building permit under the ADS permit type.
King County Depends at-grade patios and uncovered decks 30 inches or less above ground are exempt; covered patios and taller structures require a building permit.
Pierce County Depends 30 inches At-grade patios, treated the same as exempt sidewalks and driveways, are exempt if not more than 30 inches above grade at any point and not over any story or basement below; an attached, roofed patio cover requires a building permit regardless of size.
Snohomish County Depends 200 sq ft open at-grade patios are treated as exempt sidewalks and driveways under SCC 30.50.103(1)(e) with no size limit; freestanding patio covers (roofed, not attached to another structure) are exempt only if 200 sq ft or less inside the UGA or 400 sq ft or less outside the UGA; larger or attached patio covers require a permit.
Tacoma Depends at-grade flatwork such as sidewalks and driveways is exempt from a building permit, though separate site-development permits can apply; covered patios require a building permit.
Thurston County Depends 30 inches Patios and porches are exempt if 30 inches or less from the ground to the top of the surface.

Shed

All 8 make the shed answer turn on a size or scope condition the jurisdiction publishes, and the 8 that state a number publish figures from 120 to 200 sq ft.

Jurisdiction Permit Published figure What the rule says
Bellevue Depends 200 sq ft detached storage sheds playhouses or gazebos with a floor area of 200 square feet or less do not require a building permit; structures over 200 square feet require a permit.
Clark County Depends 200 sq ft Sheds over 200 square feet require a building permit; sheds of 200 square feet or less are exempt if they meet setbacks and easements, but any size shed in a mobile home park or multi-family zone requires a permit.
King County Depends 200 sq ft storage sheds 200 sq ft or less as accessory to a residential house do not require a building permit in unincorporated King County; sheds over 200 sq ft require a permit.
Pierce County Depends 200 sq ft One-story detached accessory structure used as an unheated tool or storage shed, playhouse, or similar use is exempt if its floor area is 200 sq ft or less and it is at least 3 feet from a property line; larger or closer structures require a building permit.
Seattle Depends 120 sq ft one-story detached storage sheds with a roof footprint of 120 square feet or less on a slab foundation and not in an environmentally critical area do not require a permit.
Snohomish County Depends 200 sq ft one-story detached accessory structure not used for human habitation (tool/storage shed, playhouse) exempt if floor area is 200 sq ft or less and sidewalls 9 ft or less inside the Urban Growth Area (UGA), or 400 sq ft or less and sidewalls 11 ft or less outside the UGA; larger structures require a building permit.
Tacoma Depends 200 sq ft one-story detached accessory structures with a floor area of 200 square feet or less do not require a building permit; structures over 200 square feet require a permit.
Thurston County Depends 200 sq ft One-story detached accessory buildings with no plumbing or electricity are exempt if under 200 square feet inside a county urban growth area or under 400 square feet outside a UGA.

Pool

7 of 8 make the pool answer turn on a size or scope condition the jurisdiction publishes, and the 7 that state a number all publish 24 inches. Seattle requires a permit for pool work regardless of size.

Jurisdiction Permit Published figure What the rule says
Bellevue Depends 24 inches swimming pools over 24 inches deep require a permit with plan review; above-ground pools 24 inches or less may be exempt.
Clark County Depends 24 inches A permit is required for any structure intended for swimming or recreational bathing that contains water over 24 inches deep, including in-ground, aboveground and on-ground pools, hot tubs and spas.
King County Depends 24 inches prefabricated above-ground pools less than 24 inches deep and not exceeding 5000 gallons are exempt; all other pools require a building permit in unincorporated King County.
Pierce County Depends 24 inches Prefabricated swimming pools accessory to a single family residence (Group R-3 occupancy) are exempt if less than 24 inches deep, with no separate gallon volume cap; in-ground pools and pools 24 inches deep or deeper require a building permit. Self-contained spas and hot tubs installed entirely above ground and not connected to the potable water system or a septic or sewer drain are separately exempt regardless of depth.
Snohomish County Depends 24 inches prefabricated swimming pools regulated under the IRC (one- and two-family dwellings) exempt if less than 24 inches deep, with no gallon-volume cap; in-ground pools or pools 24 inches deep or more require a building permit.
Tacoma Depends 24 inches prefabricated above-ground pools less than 24 inches deep and not greater than 5000 gallons are exempt; all other pools require a building permit.
Thurston County Depends 24 inches Pools are exempt only if prefabricated, entirely above ground, less than 24 inches deep, and under 5,000 gallons capacity.
Seattle Permit required A building permit is required for residential swimming pool and hot tub installations in Seattle.

Roof Replacement

King County and Seattle require no roof replacement permit at all. 5 of 8 make the roof replacement answer turn on a size or scope condition the jurisdiction publishes. Clark County requires a permit for roof replacement work regardless of size.

Jurisdiction Permit Published figure What the rule says
King County No permit Replacement of roofing or siding on a detached one or two-family house does not require a building permit in unincorporated King County.
Seattle No permit Replacing roof sheathing or repairing the roof on a detached one- or two-family house in Seattle does not require a building permit if no changes are made to the building envelope and the work is equal quality to the existing structure.
Bellevue Depends permit required when modifying or replacing the roof sheathing or making structural changes; simple shingle replacement may not require a permit.
Pierce County Depends 7.5 lbs per sq ft Re-roofing of a Group R, Division 3 one or two family dwelling, or a Group U private garage, carport, or accessory structure, with a roof slope greater than 2:12, is exempt if the total load of all roof coverings does not exceed 7.5 lbs per sq ft; the exemption does not apply to vegetated roofs or to replacement of roof sheathing.
Snohomish County Depends 2 layers re-roof overlay or tear-off-and-replace of a residential roof exempt if limited to 2 total layers of roofing material, uses the same type of roofing material as the existing roof, and the roof sheathing is not removed or replaced; adding a layer beyond 2, changing material type, or replacing sheathing requires a permit.
Tacoma Depends removing and replacing existing roof coverings with the same type does not require a permit; adding a layer or changing roofing materials requires a permit and pre-roof inspection.
Thurston County Depends Roof repair and replacement is exempt unless the work adds skylights or changes, repairs, or replaces structural elements or the roof pitch or slope.
Clark County Permit required Re-roofing permits are required for all buildings in Clark County; a separate permit may be required if structural work such as replacing roof sheathing is necessary.

Solar

4 of 8 make the solar answer turn on a size or scope condition the jurisdiction publishes, and the 3 that state a number publish figures from 3.5 to 4 lbs per sq ft. 4 require a permit for solar work regardless of size.

Jurisdiction Permit Published figure What the rule says
Bellevue Depends 3.5 lbs per sq ft electrical permit required for all solar systems; building permit not required for rooftop single-family systems with dead load under 3.5 lbs per sq ft and panels no more than 18 inches above roof surface.
King County Depends 4 lbs per sq ft roof-mounted solar PV panels weighing less than 4 pounds per square foot on residences do not require a building permit; heavier installations require a permit.
Snohomish County Depends 3.5 lbs per sq ft ground-mounted residential solar PV systems never need a building or mechanical permit; roof-mounted residential PV on a detached single-family house is exempt from a building/mechanical permit only if total dead load is 3.5 lbs per sq ft or less (up to 4.5 lbs per sq ft for frameless panels on a 3:12 or steeper slope, or 5 lbs per sq ft for frameless panels on a 5:12 or steeper slope), panels are mounted 18 inches or less above the roof surface, and an electrical permit has already been issued; a separate electrical permit through WA L&I is always required regardless.
Thurston County Depends Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit.
Clark County Permit required Separate SOL permits are required for ground mounted units or panels mounted on existing buildings; in new construction the solar panels are included in the NHC or ADS permit.
Pierce County Permit required In unincorporated Pierce County a building permit is always required for a residential rooftop solar photovoltaic system, regardless of size, issued through Pierce County Planning and Public Works.
Seattle Permit required A permit is required for all residential solar photovoltaic installations in Seattle.
Tacoma Permit required Residential rooftop solar in Tacoma requires a building permit from Planning and Development Services and an electrical permit issued by the city, plus a Tacoma Power interconnection agreement before the system is energized.

HVAC

1 of 8 makes the HVAC answer turn on a size or scope condition the jurisdiction publishes. 7 require a permit for HVAC work regardless of size.

Jurisdiction Permit Published figure What the rule says
Thurston County Depends Heating and cooling equipment and gas piping require a Minor Permit, but replacement of electric forced-air heating units and water heaters is exempt.
Bellevue Permit required A mechanical permit is required in Bellevue for all HVAC installations and replacements including like-for-like furnace and heat pump replacements.
Clark County Permit required Mechanical permits cover installation of heating and cooling equipment such as furnaces, heat pumps, A/C units, ductless mini splits and gas piping; for additions and new construction this work is included in the ADS or NHC permit.
King County Permit required A mechanical permit is required in unincorporated King County for installation or replacement of HVAC equipment including furnaces, air conditioners, heat pumps, fireplaces, and wood-burning stoves.
Pierce County Permit required Pierce County Planning and Public Works requires a mechanical permit for the installation or replacement of permanently installed residential HVAC equipment, such as furnaces, heat pumps, and air conditioners, in unincorporated Pierce County.
Seattle Permit required A mechanical permit is required in Seattle for installation or replacement of HVAC equipment including furnaces, heat pumps, and air conditioning systems.
Snohomish County Permit required Snohomish County Planning and Development Services requires a mechanical permit for the installation or replacement of permanently installed residential HVAC equipment, such as furnaces, heat pumps, and air conditioners, in unincorporated Snohomish County.
Tacoma Permit required A mechanical permit is required in Tacoma for the installation, replacement, or alteration of HVAC systems including furnaces and heat pumps.

Plumbing

1 of 8 makes the plumbing answer turn on a size or scope condition the jurisdiction publishes. 7 require a permit for plumbing work regardless of size.

Jurisdiction Permit Published figure What the rule says
Bellevue Depends permit required for new plumbing, concealed piping, and fixture additions; replacing a sink toilet or faucet not concealed in a wall does not require a permit.
Clark County Permit required A plumbing permit is required for installation of any plumbing fixtures, including water heaters, toilets and sinks.
King County Permit required Residential plumbing and gas piping permits in unincorporated King County are issued by Public Health Seattle and King County not by the King County Permitting Division.
Pierce County Permit required Pierce County Planning and Public Works requires a residential plumbing permit for work on the water supply or drainage system in unincorporated Pierce County, including new installations and added or relocated fixtures.
Seattle Permit required Residential plumbing and gas piping permits in Seattle are issued by Public Health Seattle and King County, not by SDCI. All piping inside the building is regulated by the health department.
Snohomish County Permit required Snohomish County Planning and Development Services requires a residential plumbing permit for any work on the water supply or drainage system in unincorporated Snohomish County, including new installations and relocated or added fixtures.
Tacoma Permit required Plumbing permits are required for all plumbing work in Tacoma including fixture replacement, drain work, and appliance installation.
Thurston County Permit required No permit is needed only to clear a blockage or to repair or stop a leak in a drain, water, soil, or vent pipe.

If the work is already built

Washington has no statewide fine for building without a building permit. The State Building Code Act, RCW 19.27, hands enforcement to local government: RCW 19.27.050 requires the state building code to be enforced by counties and cities, so stop work orders and fines for unpermitted construction come from your city or county ordinance, not from a state statute.

Washington penalties, the after-the-fact path, and what the statute actually says

The 80 answered rules come from 58 official sources, each linked from the permit page behind every jurisdiction name. See the full picture for the state on the Washington permit requirements page, or the national view of which projects need a permit at all on Do you need a building permit?

This page compiles what each Washington jurisdiction publishes, with a last checked date. It is not legal advice, and a project that is exempt from a building permit can still need zoning approval or a trade permit. Confirm with the office linked from the jurisdiction's page before you build.