Sonoma County, CA Landscaping Rules: Grass Height Limits (2026)

Unincorporated Sonoma County does not impose a uniform maximum lawn or grass height in inches. Instead, two separate rule sets govern grass: 1) Chapter 13A (Abatement of Hazardous Vegetation and Combustible Material) requires property owners to remove or trim dry grass, weeds, and combustible vegetation that creates a fire hazard, particularly in the 100-foot defensible-space zone around structures and 10 feet from roadways and driveways; the Fire Warden/Fire Marshal enforces, and inspection ramps up after the State Fire Marshal declares fire season (typically June 1). 2) For new and rehabilitated landscapes, Sonoma County Code §7D3 (Water Efficient Landscape Regulations) implements the State MWELO and caps cool-season turf lawns: for residential projects after October 4, 2022, grass lawns are prohibited unless compliant with the Water Efficient Landscape Regulations, and overall grass lawn area is capped at no more than 2,500 sq ft per site unless project-specific MWELO compliance is demonstrated. Permit Sonoma reviews landscape plans through the building permit process. Aesthetic blight from dead lawns or knee-high turf in a residential yard outside fire season can also be cited under County Code property-maintenance and nuisance provisions and individual city codes (Santa Rosa, Petaluma, Sonoma).