As of 2023, California continues to introduce progressive ADU laws, easing restrictions and fostering a more accessible and cost-effective environment for constructing Accessory Dwelling Units. This legislative evolution has led to a substantial increase in ADU construction across the state. In the previous year, ADUs constituted approximately one-seventh of permitted homes in California. Here are the key highlights of the newly enacted ADU laws, effective as of January 2023:


Changes to the 60-Day Rule

Assembly Bill 2221 mandates that all entities responsible for assessing ADU plans, including planning departments and utility companies, must provide a response within 60 days from the date of plan submission. This modification will result in a reduced timeframe for the review and processing of applications.

Revised ADU Height Restrictions

AB 2221 has also modified the height limitations as outlined below:

  • 16 ft: Permissible under any circumstances.
  • 18 ft: Permissible if the proposed ADU is located within ½ mile of public transit or the property already features a two-story multi-family dwelling.
  • 25 ft: Permissible if the ADU is connected to the main dwelling, contingent on the property’s underlying zoning code (with the most restrictive limit taking precedence).

Redefined Setbacks

Previously, setbacks were reduced to four-foot side and rear yards. Now, for proposed ADUs with a size under 800 sq. ft., the front setback requirement no longer stands as an impediment to the construction of the ADU.

Unpermitted Conditions

Senate Bill 897 eliminates the restriction regarding non-conforming zoning conditions, building code violations, or unpermitted structures. Prior to SB 897, homeowners were required to have unpermitted structures brought up to current codes, which made California ADU development slower and more costly. SB 897 removes these restrictions unless the unpermitted condition is a health or safety concern.

Fire Sprinkler Requirement

SB 897 allows fire sprinklers to no longer be required for the main dwelling when permitting an ADU.

Other Changes Worth Mentioning

  • Attached JADUs no longer need their own bathroom, provided one is accessible in the primary dwelling.
  • Demolition permits can no longer be withheld if the ADU permit has been issued.
  • The creation of the California ADU Fund to provide assistance to eligible recipients.

In 2022, the California ADU law that gained the most attention was Senate Bill 9. This relates to duplexes and lot splits. SB 9 provides for the ministerial approval of converting existing homes occupied by a homeowner into a duplex if certain eligibility restrictions are satisfied. It also allows a single-family home lot to be split into two lots, and a duplex to be built on each lot, provided that the initial home is occupied by the owner as their primary residence for at least three years.

Some key points of SB 9:

  • Projects must be for residential use only.
  • Properties are within an urbanized area designated by the City and are not within agricultural, historic, and very high fire severity zones.
  • Parking requirements need to be met unless ½ mile from public transportation stop.
  • Project will be subject to local short-term rental requirements.
  • May include connected structures (duplex) if they comply with building code safety standards.
  • If a lot is split, the project may be subject to City or County easements and must be roughly split in half.
  • Lots must meet minimum size requirements for a lot split.
  • Lot cannot be adjacent to another lot that has been split using SB 9.
Please keep in mind there are exceptions and restrictions to SB 9 that need to be fully understood.

Summary of Recent ADU Laws in California:

  • Faster ADU plan review times.
  • Prohibits local agencies from imposing strict requirements that exceed state mandates.
  • More flexible ADU size and setback requirements.
  • Allows both regular-size and “Junior” ADUs on the same property.
  • A JADU may be constructed inside the walls of a single-family home and is not required to include a bedroom or an interior entry into the home.
  • Allows ADUs for multi-family units and duplexes.
  • Prohibits local agencies charging “Impact Fees” for ADUs under 750 sq. ft.

Other Highlights

AB 68 allows landlords and homeowners to add 2 more units – an ADU and a Junior Accessory Dwelling Unit (JADU) – on any residential lot. This means you can legally create a triplex on every single lot in the state according to the new ADU laws in California.

Additional units can be added to existing multi-family buildings like apartment complexes. Building owners can convert any non-habitable rooms, like attics, basements, garages, etc. into legal additional units.

Under AB 68, municipalities will be required to approve the following:

  • One ADU (up to 1,200 sq. ft.) and one Junior ADU (a unit of no more than 500 sq. ft. in size and contained entirely within an existing single-family structure) per lot.
  • One detached ADU (up to 1,200 sq. ft.) that is new construction, existing structure, or the same footprint as the existing structure, along with one JADU.
  • Multiple ADUs within existing multifamily structures.
  • Two detached ADUs on a multi-family lot.

Other Restrictions that are Prohibited by Local ADU Laws

To further remove barriers to the approval of ADU plans in California in 2023, various state laws prohibit local governments from imposing the following:

  • May not impose requirements on lot coverage or minimum lot size.
  • May not require replacement parking when a garage, carport, or covered parking structure is demolished to create an ADU or is converted to an ADU.
  • HOAs may not “prohibit or unreasonably restrict” the construction of ADUs on single-family residential lots.
  • Local agencies may not impose impact fees on ADUs under 750 sq. ft.
  • Eliminates the requirement for owner-occupancy of either the primary dwelling or the ADU. JADUs still require owner occupancy.

Interpreting the Law

Please note that this summary is based solely on the State Ordinance. Therefore, it is important to note that each City and County will release its own ADU rules and regulations in response to the new state laws. Some Cities and Counties may defer the effective date or challenge the state through legal channels in order to meet their own codes. Variations of these State rules will differ in each city and county.

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