San Marcos, CA Environmental Rules: Defensible Space (2026)

6, to require that anyone owning, leasing, controlling, operating or maintaining a building or structure in, upon or adjoining a hazardous fire area maintain an effective fuel modification zone by removing, clearing or modifying combustible vegetation and flammable materials within 150 feet of the structure. Replanting within that zone is limited to approved irrigated, fire-resistant plants or approved non-irrigated, drought-tolerant, fire-resistant plants, and may be required for erosion control. Three exceptions apply: single specimen trees or ornamental shrubs that will not rapidly transmit fire; grass and vegetation more than 30 feet from a structure and under 18 inches tall needed for erosion control; and, with FAHJ approval, a reduced zone where fire-resistive construction is used, though the zone can never drop below 100 feet and existing structures cannot be forced into fire-resistive retrofits to justify the reduction.

8, lets the FAHJ require a property owner to clear combustible vegetation within 20 feet of each side of a driveway or adjacent public or private road to create a roadside fuel modification zone, though the FAHJ may reduce that width if it will not impair emergency access. 3 separately sets structure setbacks from the top of a slope: single-story structures must sit at least 15 feet horizontally from the slope's top edge and stay under 12 feet above grade, while two-story structures need a 30-foot horizontal setback. The chapter notes that wherever it conflicts with other referenced fire codes, the more restrictive requirement controls.