SB9 Lot Splits: What California Owners Should Know

The short version

SB9 allows eligible single-family lots in California to be split into two parcels, and each parcel to hold up to two units. In practice, the rules are narrower than the headlines suggest.

Eligibility checkpoints

• The lot must be in a single-family residential zone within an urbanized area.
• The split must create two parcels of roughly equal size, each at least 1,200 square feet.
• Historic districts, hazard zones, and certain protected housing situations are excluded.

Where engineering matters

Access, utilities, and drainage decide feasibility more often than zoning does. Each new parcel needs legal access and separate service connections, and grading has to keep runoff from crossing the new property line in unmanaged ways.

Our recommendation

Run a short feasibility review before you spend on design. A few days of survey and utility research usually answers whether a split is worth pursuing.