Washington County, OR Fire Regulations: Brush Clearance (2026)

D requires owners of dwellings and structures, including replacement dwellings and accessory structures in the EFC District, to maintain a minimum 30-foot primary fuel-free fire break area around the building. That distance is not fixed: Table A increases the primary safety zone's additional buffer as slope rises, adding a 50-foot additional safety zone at 10% slope, 75 feet at 20% slope, 100 feet at 25% slope, and 150 feet at 40% slope, on top of the base 30-foot primary zone. Owners must also maintain an additional 100-foot secondary fuel-free fire break encircling the primary break.

Any required fire break must sit on land the property owner owns or controls, meaning a firebreak cannot be maintained on a neighbor's parcel. B must meet these same fire break requirements to the extent the existing building setbacks allow. The fuel-free break requirement pairs with related structural standards in the same section: structures cannot be sited on a slope greater than 40%, must have a fire-retardant roof, and any chimney must carry a spark arrester. 5 separately requires roads and driveways serving these structures to be built and maintained to standards approved by the local fire protection agency, with written confirmation required before both preliminary and final building inspection.