What is SB 9 in California?

Lots zoned single-family in urbanized areas. Excluded: most historic districts, very-high fire severity zones without mitigation, wetlands and farmland. A lot split requires each new parcel to be at least 1,200 square feet and roughly 40 percent of the original, and the owner has to sign an affidavit agreeing to live on one of the parcels for three years.

In April 2024 a Los Angeles trial court held SB 9 unconstitutional as applied to charter cities, but the writ it issued bound only the five South Bay cities that had sued. The state appealed. In November 2025 the Court of Appeal reversed that judgment and sent the case back to the trial court to reconsider under amended legislative findings, expressing no view on the merits. A separate published 2025 decision upheld SB 9 as applied to general law cities.

The practical answer: SB 9 is in effect, the City of Los Angeles was never bound by the 2024 ruling and processes SB 9 applications today, and the charter-city question remains unresolved on remand. We check the current status before anyone commits money to a design.

A two-unit SB 9 project can often include ADUs as well, and after a lot split each new parcel can host its own units. The City of Los Angeles handles SB 9 through a planning implementation process rather than a standalone local ordinance, so the details are worth confirming parcel by parcel.