SB 9

Nickname: California Home Act

Subject: Duplexes and Lot Splits

Sponsor: Sen. Atkins

Year: 2021

Bill Text

What is it?

This bill gives owners of single-family zoned property the ability to split their lots into two parcels and develop a duplex on each. This allows people to build more housing for more people in a state in which nearly two-thirds of all the residences in California are single-family homes. However, there are many restrictions built into the law as well.

Check out our guide for a more detailed look.


  • The owner of an SB9 property has to sign an affidavit saying that one of the homes will be their primary residence and will be owner-occupied for at least three years.
  • SB9 only applies to US Census urban areas only and excludes certain land use designations, such as historic districts, earthquake fault zones and very high fire hazard severity zones. 
  • Resulting parcels must be a minimum of 1200 sq. feet with at least one parking space per unit.
  • An SB9 development can’t require the demolition of any rent-controlled units and or units that have been occupied by a tenant in the past three years.
  • Lastly, and most significantly, SB9 gives local governments free rein to impose local development standards as long as those standards would not “physically preclude” a duplex. Many local governments have already taken this allowance to enact excessive local standards that would make developing under the law financially infeasible.