California SB-9

California SB-9 is a state housing law (enacted in 2021, generally effective in 2022) created to add homes on land previously reserved for single-family houses. In broad strokes it offers two mechanisms for qualifying single-family parcels: an urban lot split that divides one lot into two, and the ability to build up to two units on a parcel. Combined, these can allow significantly more homes where only one house was previously permitted.

The headline feature for builders is ministerial, by-right approval. Where a project meets the law's objective standards, the city is generally required to approve it without the discretionary review and public hearings that add time and uncertainty. That predictability — not just the added density — is what makes SB-9 meaningful for people who build for a living, and it is part of the broader push to re-legalize missing middle housing.

SB-9 comes with conditions and guardrails. It generally targets parcels zoned for single-family residential use, requires projects to meet objective standards, and excludes or restricts categories such as certain historic districts and some environmentally sensitive or hazard areas. It also includes anti-displacement provisions and an owner-occupancy intent affidavit associated with lot splits. SB-9 is distinct from SB-10, which is an optional local upzoning tool rather than a statewide entitlement.

The precise eligibility criteria, exclusions, and local objective standards vary by city and are subject to change. This is informational only, not legal advice — verify the current statute and your specific parcel with the local planning department, and consult qualified counsel before relying on SB-9 for a project.