Senate Bill 9 (SB 9) and ADU regulations offer LA County homeowners two distinct paths for property development. SB 9 allows homeowners to split their single-family lots into two parcels and potentially build up to four units total, provided they meet specific requirements including minimum lot sizes of 1,200 square feet and a maximum 60/40 split ratio. Property owners must intend to live on one of the lots for at least three years, and splits aren't allowed in certain areas like hazardous waste sites or very high fire hazard zones.
Alternatively, homeowners can build Accessory Dwelling Units (ADUs), which are secondary units added to existing properties. Detached ADUs are typically limited to 1,200 square feet and must maintain 4-foot setbacks from property lines. Recent legislation (SB 1211) has eliminated parking replacement requirements, though units must include features like separate heating, kitchens, and in some cases, solar panels. LA County no longer requires owner occupancy for ADUs, but they cannot be used for short-term rentals under 30 days.
Each approach has distinct financial implications. Lot splits can generate immediate income through land sale but might temporarily decrease property value due to reduced lot size. ADUs typically increase property value by 40-60% and provide potential rental income, though they trigger a partial property tax reassessment. The choice between these options depends on factors like financial goals, property characteristics, and timeline preferences - lot splits generally move faster but involve complex permitting, while ADUs may take longer to construct they may offer more flexible long-term benefits for multigenerational living or rental income.
Developing or redeveloping a property in a Very High Fire Hazard Severity Zone (VHFHSZ) after a wildfire may involve stricter regulations. ADUs are generally prohibited unless there are two wide, unobstructed access roads to a highway . Lot splits may be allowed if they meet fire safety and mitigation requirements , such as defensible space and fire-resistant construction. Access roads in Hillside Management Areas must be paved . It's crucial to consult with LA County officials and prioritize fire safety measures due to the recent catastrophic wildfire. Portions of Altadena, CA fall within a Very High Fire Hazard Severity Zone (VHFHSZ). You can verify your specific address using the Los Angeles County Fire Department's online tool.
More information on:
AB-38 and Real Estate Sales in California's High and Very High Fire Hazard Severity Zones
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