California density playbook
SB-9
Single-family lot split + duplex
Splits an R-1 lot in two and allows up to two units on each new lot. Ministerial approval, no public hearing.
In plain English
What it actually does.
SB-9 took effect January 2022 and re-shaped what's possible on virtually every R-1 parcel in California. A qualifying lot can be split into two parcels of at least 1,200 sf each, and each new parcel can hold a duplex — yielding four primary units where one stood. Stack ADU rights and the count can rise to six.
How it applies
On the ground, by city.
01 / City
Los Angeles
Ministerial review; coastal and historic overlays apply.
02 / City
Beverly Hills
Ministerial; objective design standards enforced.
03 / City
Newport Beach
Coastal zone parcels require additional Coastal Commission review.
Keep reading
Other laws in the playbook.
Run the numbers
See what SB-9 unlocks on your lot.
Drop in your address, lot size, and zoning. The calculator returns a unit count, the pathway, and the warnings worth knowing.
Open the lot calculator