Guide to Single-Family Zoning in California

You may have heard that there are some big changes to single-family zoning laws in California. Whether you are a homeowner, an aspiring homeowner, or a concerned citizen, here’s what you need to know.

What is single-family zoning?

When a plot of land, also known as a parcel or lot, is zoned as single-family, this generally means the owner of the land can only have one primary property unit on it, usually a house. That said, the law also allows for a smaller secondary unit, or accessory dwelling unit (ADU), sometimes called a granny flat.

Also, as of January 2022, a new law allows many “single-family” lots to have up to 4-units, essentially converting them into 4-unit maximum lots.

Does California still have single-family zoning?

Yes. Although a new law significantly modifies many single-family designated lots in the state, some single-family lots are unaffected. The law only applies to urban areas, and specifically exempts farms, wetlands, historic districts, and lots at high risk of fire or flooding. So, these types of lots would still be single-family only (assuming they are already zoned as single-family).

What are the new changes to single-family zoning?

As of January 2022, California Senate Bill 9 (SB 9) allows owners of certain single-family lots to build up to 4 units on them. In order to reach the maximum of 4 units, the owner would need to subdivide the lot into two separate lots, and then each sub-lot could have up to 2 units. The subdivided lots must be at least 1200 square feet each, and roughly the same size.

Here are the other requirements of the new law:

  • Only applies to urban areas
  • Exempts: farms, wetlands, lots at high risk of fire or flooding; sites in historic districts
  • You may not alter or demolish any units reserved for low-income housing or that had been rented within the previous three years (to avoid reducing the supply of rental and affordable units)
  • The person applying to subdivide a lot must live in one of the units for at least 3 years
  • You may not use any of the units for short-term rentals (Airbnb etc)
  • Units can be at least 800 square feet, and may be adjacent or connected

Do local governments still have any say over these lots?

Yes. Local governments (city or county) can still impose reasonable safety and aesthetic standards, such as where on the lot the units can be placed, setbacks from the street, etc. They cannot require that you build more than one parking spot per unit, and they can’t require any parking spaces if the units are within half mile of public transit.


For help with understanding whether the law impacts your property, speak to a land use or real estate lawyer. You can find out more about getting legal help in California.

Photo credit: Photo by Avi Waxman on Unsplash

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