Sonoma County, CA Property Maintenance: Vacant Lot Maintenance (2026)

Vacant lots in unincorporated Sonoma County are governed mainly by the fire-driven vegetation rules in Chapter 13A of the County Code, 'Duty to Maintain Defensible Space and Abate Hazardous Vegetation and Combustible Material.' All hazardous vegetation or combustible material on real property in the unincorporated area is 'deemed a public nuisance.' For unimproved parcels in the State and Local Responsibility Areas, Section 13A-4 requires owners to: remove flammable vegetation and other combustible growth within 10 feet of structures and roadway frontage; remove dead and dying vegetation within that 10-foot zone; trim grass and combustible surface vegetation within 10 feet of structures and roadway frontage to less than 4 inches in height (unless needed for erosion control); prune all trees within 10 feet of structures and roadway frontage to at least 6 feet above grade; and remove combustible material from the property. The County Fire Warden/Fire Marshal is the enforcing officer and may inspect, issue a notice of violation and order to abate, and require abatement within 30 calendar days. Under Section 13A-6 the Fire Warden may summarily abate immediate threats. If the County abates, 'abatement costs' — including physical abatement, administration fees, and applicable attorney's fees — may be recovered and become a property lien under Government Code Sections 25845 and 25845.5. Agricultural crops and cannabis cultivation areas are exempt, but defensible space is still required around habitable dwellings.