california adu law

California ADU Laws 2022

California ADU law, enacted in 2020 and 2021, removed restrictions around building ADUs or accessory dwelling units. These laws are passed at the state level and it limits or removes the local government’s ability to remove or override them. This means it is a lot easier to understand what you can build in your own backyard.

Here is a recap of the most important points and what they mean for your future backyard home. You can read the full California Department of Housing and Community Development Accessory Dwelling Unit policy HERE.

california adu laws

California ADU Law Creates The Ideal Detached ADU

The ideal accessory dwelling unit in California

  • Under 800 SF
  • Less than 16 ft in height
  • Set Backs, 4 ft from back and sides, 6 ft from main home

A Backyard home like this is allowed anywhere in the state of California- local government can’t say “no”, and they can’t add additional permit fees (known as impact fees).

The maximum size for a detached ADU can vary by local jurisdiction.

Reduced Permit Fees

Impact fees are additional permit fees added by local government when homeowners add living space to their homes. The fees are supposed to offset growing infrastructure costs like schools and roads. These fees can add anywhere from $3,000 – $30,000 to a construction project.

The new California ADU laws prohibit these impact fees for any ADU that is less than 750 sf.

Add More Than One ADU

In general- a homeowner can add one detached ADU and one attached Junior ADU (JADU) per single family home.

SB-9 is a very recent California ADU law that allows a homeowner to split their lot into two lots. Each lot can have a home and an ADU for a total of 4 housing units and the separate lot can be sold. The homeowner must occupy one of the units.

No Lot Size Restrictions

There are no restrictions regarding lot size or lot coverage. This means even small lots can add a backyard home.

No Owner Occupancy Requirements

The homeowner is not required to live in any of the housing units. Prior to the new state accessory dwelling laws individual cities could choose to require owner occupancy.

This means investors are able to add ADUs and JADUS to create more rental housing.

Reduced Parking Requirements

You are not required to add off-street parking as long as your site is within 1/2 miles from a public transportation stop.

HOA and Historic Districts Can’t Say No

You can add an ADU even if your home owner’s association laws restrict or prohibit them. This is also true for historic overlay districts. They can impose requirements around aesthetics and visibility- but they can’t say no.


Can I build a two-story Backyard House?

It depends on your local jurisdiction. The local planning department will review your plans and determine if they will allow a second story. California ADU Law only ensures you can build a backyard home that is under 16 ft in height. A lot of cities in the Los Angeles area are against second story ADU additions- but each situation is unique.

How about an ADU over my garage?

This is nearly the same answer as above. The added information is that most garages were not built to hold the weight of a second-story addition. If your area will allow a backyard home over your garage you will probably need significant structural modifications.

My garage is built on the property line. If I convert it, will the 4 ft setback rule apply?

No, but that is ONLY if you convert within the original footprint of the garage. Expanding in any direction triggers the 4 ft setback rule. Read: ADU Garage Conversion FAQ

What is the largest ADU allowed under California ADU law?

The largest Backyard home allowed under California ADU law is 1200 sf. However, your local jurisdiction has the authority to approve or deny any backyard home over 800 SF.

Is An ADU Possible In Your Backyard?

Does your backyard qualify under the new California ADU laws? Get our Free Consultation to find out what is possible for your property.

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