Colusa County, CA Building Setbacks & Zoning: Lot Coverage Limits (2026)

Unlike many jurisdictions, the Colusa County Zoning Code (Article 44-2) does not set a maximum lot-coverage percentage for residential zones. Instead, building bulk in the residential zones is controlled by minimum setbacks and a maximum structure height (30 feet in R-R, R-1, and R-2; 40 feet in R-3 and R-4) rather than a footprint-percentage cap. For commercial and industrial zones, intensity is regulated by Floor Area Ratio (FAR) - the ratio of total building floor area to lot area - with limits set in the development-standards tables (for example FAR values such as 0.4, 0.5, 0.6, 0.75, and up to 1.5 depending on the zone). A coverage-related limit that does apply in the single- and multi-family residential zones (R-1 through R-4) comes from Article 44-3 (Site Planning Provisions): no more than 50 percent of a required front and side setback may be covered with paving or other impervious surfaces, and the remaining front-setback area must be landscaped or kept as open space, with impervious surfaces in setbacks limited to driveways, walkways, and similar improvements. Increased maximum lot coverage and FAR are among the concessions available through the state density-bonus program referenced in Article 44-3. Owners planning extensive site coverage should confirm the applicable FAR and impervious-surface limits with the Planning Division.