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

There is no county ordinance setting a maximum lawn or yard grass height for aesthetics in unincorporated Siskiyou County. The one place the County Code states a grass-height number is its wildfire-defense rule, the Siskiyou County Fire Control and Fire Hazard Regulations (County Code Title 3, Chapter 3). Under Section 3-3.02.1, owners of buildings on mountainous, forest-, brush- or grass-covered land must clear all flammable vegetation for at least 30 feet around each structure (or to the property line). Section 3-3.02.2 then requires additional clearance from 30 to 100 feet from the building. Within that 30-to-100-foot zone, the code says grass and other vegetation may be left in place where needed to stabilize soil and prevent erosion only if it is kept less than 18 inches in height above the ground. So the practical "grass height" rule in the county is a fire-safety standard: tall grass close to a home must be removed, and any grass left in the outer defensible-space zone for erosion control must stay under 18 inches. This county code complements the statewide 100-foot defensible space requirement of Public Resources Code 4291, which applies because nearly all of unincorporated Siskiyou County is a State Responsibility Area. Routine mowing of an ordinary yard is not separately regulated.