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

There is no Marin County Code section that imposes a single uniform 'grass-must-be-X-inches-tall' rule countywide. Instead, the operative standard is Marin County Fire Code Ordinance No. 3775, § 325.5 (Abatement of Hazard) and § 325.5.1 (Weeds, dead trees and rubbish to be destroyed or removed), which makes it unlawful for any person with an ownership or possessory interest in a parcel to allow hazardous rubbish, weeds, trees, or other vegetation that constitutes a fire hazard. § 325.6 (General abatement requirements) and § 325.9 (Abatement procedures) authorize the County fire code official to order abatement of weeds, trees, and rubbish, including mailing notice to the property owner and abating the nuisance at the owner's expense if not addressed. In practice, fire agencies (Marin County Fire, Southern Marin Fire, Central Marin Fire, Ross Valley Fire) treat dry grass over 4 inches near structures as a fire hazard requiring mowing. State law (Public Resources Code § 4291) separately requires 100 ft of defensible space around structures in State Responsibility Areas, including removing dead/dying plant material.