Understanding SB 9 (California State Senate Bill 9)

By Kevin Dougherty | December 11, 2021
SB 9

I’ve heard people say recently, “there is no such thing as single-family zoning in California anymore”.  There is some truth to this but only under certain circumstances.

The California State Senate Bill 9 (better known as SB9) is a 2021 California state law that allows up to 4 units to be built in most single-family residential zones in California, regardless of existing local zoning laws.  You can use SB9 to split your lot, add a 2nd home to a lot, or both (split lot and have 2 homes on each lot for a total of 4 homes).

By increasing housing supply and diversifying the types of housing available in a given area, SB 9 aims to help alleviate the “housing crisis” while ensuring local homeowners–rather than real estate development companies–are the ones making the aesthetic decisions and the resulting profits within their own neighborhoods.

Some cheer, some cringe at the thought of higher density, more parking problems, more wear and tear on our infrastructure.  However you feel, it never hurts to arm yourself with knowledge should any questions on this topic arise.

  • Here’s a Quick Guide from the California Association of Realtors that does a good job of summarizing the key elements of SB-9
  • Or for a little more detail you can view the full Slide Deck as well.
  • And if you’re the kind that would rather watch an Informational video, you have that option too.

SB9 takes effect on January 1, 2022.

You can find the detailed language of the bill at the California Legislative Information website at:


To further discuss this or any other topic, please feel free to reach out and get ahold of me at:
Kevin Dougherty
(619) 977-7777