Do You Need a Fence Permit in Washington State?

A fence permit is not a separate statewide permit type. It is the building or construction permit a city or county requires when a proposed fence falls outside the permit exemptions in its adopted residential code, or when zoning, critical-area, or flood rules call for review.

Two different sets of rules apply to the same fence. The building code decides whether a permit is required, usually based on height and construction. The zoning code decides where a fence may stand and how tall it may be in each part of the lot. A fence can be exempt from a building permit and still be too tall for its location under zoning.

Fences sit on or near property lines, inside setbacks, and over buried utilities, so mistakes are expensive to undo. An over-height or misplaced fence may have to be cut down or moved at the owner's cost, and a post driven into a utility line creates a safety and liability problem.

Confirming the permit and zoning position before materials are ordered keeps the height, layout, and schedule in a proposal realistic, and makes clear whether the owner or the contractor is responsible for checking them.

Washington adopts the 2021 International Residential Code by reference in chapter 51-51 WAC, and the state amendments do not change the code's permit-exemption section. The model code exempts fences not over 7 feet high from a building permit, but cities and counties may adopt their own amendments, and many do.

Seattle shows how far local rules can move from the model code. Its residential code allows a fence up to 8 feet high without a permit when it has no masonry or concrete elements over 6 feet and is not in a flood-prone area, while its zoning code limits fences in neighborhood residential and multifamily zones to 6 feet, plus 2 feet of architectural features, and to 4 feet in a front or street side setback.

Digging post holes is excavation under Washington's underground utilities law. Chapter 19.122 RCW requires an excavator to mark the dig area and notify the one-number locator service at least two full business days before work begins. The exemption for an owner or occupant digging on private noncommercial property covers only excavation less than 12 inches deep, which fence post holes typically exceed.

Placement also has a legal dimension beyond permits. RCW 7.40.030 allows a court to order the removal of a structure maliciously erected to spite, injure, or annoy an adjoining owner.

For owners, start with the property rather than the product: confirm where the property line actually is, whether an easement crosses the fence route, which zoning setbacks apply to each side of the lot, and whether covenants or HOA rules add their own limits. A survey or recorded plat is more reliable than an existing fence or a neighbor's recollection.

For contractors, put responsibility in writing: who confirms the line, who submits the utility locate request, who obtains any required permit, and what finished height is being quoted on sloped ground. Fence installers commonly price a project after an on-site measure — Vista Fence in the Greater Seattle area, for example, books a free measure after an online estimate — and that visit is the natural point to settle these questions before the contract is signed.

Washington sets the statewide framework: the adopted residential code, contractor registration under chapter 18.27 RCW, and the underground utilities law. The numbers that decide most fence projects are local — the permit height threshold after local amendments, fence height limits by yard and zone, and any critical-area, shoreline, or corner-visibility restrictions. Check the city or county where the property sits, because a fence that is routine in one jurisdiction can need a permit or a lower height a few miles away.

• Treating the building-permit exemption as permission to build to that height anywhere on the lot; zoning limits can be lower, especially in front yards.
• Measuring height from the wrong point on sloped ground, or ignoring a retaining wall below the fence.
• Setting posts without a utility locate because the holes are dug by hand.
• Assuming an old fence marks the property line.
• Building across a recorded easement without checking what the easement holder may require.
• Relying on another city's fence rules, an outdated code edition, or a verbal answer without checking the official source.