Two lots where you had one
SB 9 lets a single-family lot be split in two, with up to two homes on each. Unlike an ADU, the new lot can be sold on its own.
You're likely a fit if
- A single-family zoned lot
- Not a historic district or landmark
- The split won't demolish or alter housing a tenant lived in during the last 3 years
- You'll live in one of the homes for 3 years after a split
What it looks like
The orange piece is what gets built.
How it runs
Lot size, frontage, access and whether the split works at all.
Survey, the split itself and the homes on each lot.
The city approves the split ministerially, then the building permits.
One home, two, or a sale of the new lot.
What owners ask
SB 9 or an ADU?
If you want to sell the new home someday, SB 9. If you want rent and to keep one property, an ADU is cheaper and faster.
Can I add ADUs after a split?
Generally the combined limit is two homes per lot, counting ADUs.
Where this comes from
Checked October 2026. Laws change; we re-check every project against the current code before design. General information, not legal, tax or financial advice.
| Source |
|---|
| SB 9 (2021), Gov. Code 65852.21 and 66411.7 |
| SB 450 (2024) amendments |
Other programs
Since January 2025, California lets an existing apartment property add detached ADUs, one for every existing unit up to eight, plus conversions of garages and storage.
Learn more
Cities must now keep a set of pre-approved ADU plans.
Learn more
A garage apartment or back unit built without permits can usually be legalized as an ADU.
Learn moreDoes your property qualify?
Send the address. We check it against this program and every other one.