Senate Bill 9, effective January 2022, fundamentally changed residential lot splitting. Single-family property owners can now split lots into two parcels with less regulatory friction.
SB 9 Eligibility Requirements
Your property must be zoned single-family residential, owned for at least 3 years, and not previously split under SB 9. The lot must be large enough to create two compliant parcels meeting setback, parking, and utilities requirements. No parcel can result from the split if it violates local zoning. SB 9 doesn't override zoning—it streamlines the split process for zoning-compliant divisions. Properties where a second unit would violate setbacks or parking requirements don't qualify.
Environmental Review and Utility Requirements
SB 9 requires environmental review but uses streamlined California Environmental Quality Act (CEQA) procedures. Water and sewer connections must be available to both resulting parcels. If utilities don't reach one parcel, SB 9 split is impossible. On-site septic systems complicate splits—each parcel needs adequate septic capability. Cost of utility infrastructure to reach both parcels can eliminate split economics, especially in rural areas where sewer connections don't exist.
Value Impact and Development Strategy
SB 9 splits increase property value by enabling development of two homes instead of one. A $1.2 million single-family lot becomes two $700,000-capable parcels. Some owners keep one parcel, sell the other. Others develop both. SB 9 splits work best on larger R-1 lots (10,000+ square feet) in appreciating markets. Smaller lots may not permit two compliant parcels. Survey and engineering work costs $3,000-5,000, so small lots face unfavorable economics.