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

San Bernardino County does not regulate grass height for appearance, but it does regulate it for fire safety. Under County Code Section 23.0302 (Valley Area), Section 23.0304 (Mountain Area), and Section 23.0305 (Desert Area), 'grass over four inches in height' is defined as flammable vegetation constituting a fire hazard. The County's Fire Hazard Abatement (FHA) program enforces this. According to the County Land Use Services 'Violation Explanation' guidance, in the Desert and Valley regions weeds and grasses must be cut to no more than four inches in height throughout the property if it is less than five vacant/unimproved acres. In the Mountain region the four-inch grass standard applies for 100 feet around structures and 10 feet from roadsides. This is a fire-hazard rule, not a nuisance-weeds-for-looks rule, so it is driven by proximity to structures, roads, and wildland. The County also notes this implements California Public Resources Code Section 4291 defensible-space requirements. Parcels of five or more continuous acres of fire-hazard vegetation may instead use the alternative firebreak method in Section 23.0303. Property owners on small lots should keep grass mowed below four inches during fire season to avoid an abatement notice.