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

Lot coverage in unincorporated Riverside County is governed by zone under Ordinance No. 348. For the R-1 (One-Family Dwellings) zone, Section 6.2.G states the rule plainly: 'Lot Coverage: In no case shall more than 50% of any lot be covered by dwelling.' The same section sets a minimum lot area of 7,200 square feet, a minimum average building-site width of 60 feet, a minimum average depth of 100 feet, and a minimum street frontage of 60 feet (35 feet on cul-de-sac knuckles). These dimensional standards work together with the yard setbacks (20-foot front, 10-foot rear, percentage-based side yards) to control building bulk. The 50% coverage figure in R-1 is measured by the dwelling's footprint relative to the lot. Other zones - such as higher-density residential, agricultural, or specific commercial/industrial zones - apply different coverage percentages and minimum lot sizes; some specific-plan areas allow much higher coverage (for instance, certain planned areas permit up to 80% coverage). An asterisk legend on the zoning map (Section 18.35) can also modify the minimum lot area and other standards. Because coverage and lot-size minimums depend on the exact zone classification, owners should confirm their zone with County Planning before planning an expansion that increases footprint.