4 county-level rules, plus city-specific rules for 2 cities in Sonoma County, California.
Verified from official government sources
Sonoma County does not set a numeric lawn height limit (e.g., '6 inches'). Instead, tall grass that creates a fire hazard is regulated under Chapter 13A (Hazardous Vegetation Abatement), and turf and irrigated grass area is capped on new and rehabilitated landscapes by the Water Efficient Landscape Regulations (County Code §7D3) under California MWELO.
Sonoma County protects native trees 6 inches in diameter or greater under the Tree Protection Ordinance (Code §26-88-010(m)), with stricter rules for heritage and landmark trees (Chapter 26D), oak woodlands (§26-67), and trees in riparian corridors (§26-65). The county adopted an updated tree ordinance on April 16, 2024.
Sonoma County Code Chapter 13A (Abatement of Hazardous Vegetation and Combustible Material) requires property owners to maintain defensible space and remove hazardous vegetation in unincorporated areas. Defensible space extends 100 feet from structures, with a 'lean, clean, and green' zone in the first 30 feet and a 'reduced fuels' zone from 30 to 100 feet.
California Food & Agricultural Code § 5004
“Noxious weed” means any species of plant that is, or is liable to be, troublesome, aggressive, intrusive, detrimental, or destructive to agriculture, silviculture, or important native species, and difficult to control or eradicate, which the director, by regulation, designates to be a noxious weed. In determining whether or not a species shall be designated a noxious weed for the purposes of p...
Sonoma County's water supply comes primarily from the Russian River system managed by Sonoma Water (Sonoma County Water Agency), which serves most cities and special districts in the county. Unincorporated areas are served by smaller mutual water companies, private wells, and county service areas. Sonoma County Code Chapter 25B requires private wells to meet permit and metering standards, and the county Board of Supervisors and Sonoma Water issue coordinated drought-stage declarations that trigger outdoor watering bans, day-of-week schedules, and well-pumping restrictions. The state's MWELO (Cal. Code Regs. Title 23, §490) applies to landscape projects of 500 sq ft or more in unincorporated Sonoma County.
2 cities in Sonoma County have their own landscaping rules rules. Each link goes to that city's dedicated page with code citations.
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