R-1 and R-2 zones are California's most common residential classifications. The differences fundamentally affect property value, development potential, and neighbor composition.
R-1: Single-Family Residential Zone
R-1 zones restrict properties to one dwelling unit per lot, with rare exceptions. Typical R-1 setbacks require 20-30 feet front, 5-10 feet sides, and 25-35 feet rear. Lot minimums range from 5,000-10,000 square feet. Uses include detached houses, home offices, and accessory structures. No duplexes, multi-family buildings, or commercial uses are permitted. R-1 zones maintain single-family character and typically command higher per-acre prices due to exclusivity and consistent development patterns.
R-2: Multi-Family Residential Zone
R-2 zones permit duplex, triplex, and small apartment buildings (typically 4-8 units). Lot minimums are lower, and density maximums are higher. R-2 allows mixed-income development and workforce housing. Parking requirements increase, and building setbacks adapt for multi-family living. R-2 zones near commercial areas or transit corridors offer development economics unavailable in R-1. Investors seek R-2 zoning for multi-unit income properties.
California SB 9 Single-Family Lot Splits
Senate Bill 9 allows R-1 property owners to split single-family lots into two separate parcels, each capable of supporting one dwelling unit. This effectively converts R-1 to dual-unit potential without formal rezoning. SB 9 requires complying with setbacks, utility access, and parking rules. It's transforming R-1 economics in expensive California markets by enabling additional density without neighborhood-scale changes. Simi Valley properties eligible for SB 9 splits have appreciated accordingly.