Attachment C – Summary of Recent ADU Laws
AB 1154
AB 1154 (Chapter 507, Statutes of 2025) made various changes to State ADU Law (Gov. Code, § 66333) regarding JADUs and went into effect on January 1, 2026. This bill:
• Specifies that if a JADU has shared sanitation facilities with the primary structure, owner-occupancy will be required. If the JADU does not have shared sanitation facilities, owner-occupancy will not be required (Gov. Code, § 66333, subd. (b)).
• Requires that JADUs can no longer be used as short-term rentals and, if rented, must now be rented for longer than 30 days (Gov. Code, § 66333, subd. (g)).
SB 9
SB 9 (Chapter 510, Statutes of 2025) made various changes to State ADU Law (Gov.
Code, § 66326) regarding requirements for local jurisdictions when submitting ordinances to HCD and went into effect on January 1, 2026. This bill:
• Clarifies that if a local agency fails to submit an adopted ADU ordinance to HCD within the 60-day timeline or fails to respond to HCD’s findings regarding its ordinance within the 30-day timeline, that ordinance is null and void and the local agency must only apply State ADU Law when permitting ADUs (Gov.
Code, § 66326, subd. (d)).
SB 543
SB 543 (Chapter 520, Statutes of 2025) made various changes to State ADU Law (Gov.
Code, §§ 66311, 66313, 66317, 66320, 66323; 66324; 66327; 66325; 66332 and added sections 66335; 66335.5; and 66339.5) regarding requirements for local jurisdictions when submitting ordinances to HCD and went into effect on January 1, 2026. This bill:
• Revises the definition of a “junior accessory dwelling unit” to require the size of a JADU to be no more than 500 square feet of interior livable space (Gov.
Code, § 66313, subd. (d)).
• Expands HCD’s authority over Chapter 13 of Division 1 of Title 7 of the Government Code, including but not limited to review, adopt, amend, or repeal guidelines to additionally grant that authority with respect to terms, references, and standards for JADUs (Gov. Code, § 66311). • Revises the limitations on impact fees to, instead, prohibit impact fees upon the development of an ADU that has 750 square feet of interior livable space or less or JADU that has 500 square feet of interior livable space or less, and to require that any impact fee on an ADU that has more than 750 square feet of interior livable space be charged proportionately in relation to the square footage of the primary dwelling unit (Gov. Code, § 66311.5, subds. (a) – (d)). • Requires a permitting agency to determine whether an application for an ADU or JADU is complete and provide written notice of the determination not later than 15 business days after the permitting agency received the application (Gov. Code, § 66317, subd. (a)(2)(A)).
• Requires the permitting agency to provide the applicant with a list of incomplete items and a description of how the application can be made complete in the written notice if it is determined that an application is incomplete (Gov. Code, § 66317, subd. (a)(2)(B)).
• Requires the permitting agency to provide a process for an application to be deemed complete and for applicants to appeal an incompleteness determination or denial, as provided, and requires the permitting agency to provide a final written determination by not later than 60 business days after receipt of the written appeal if a permit application is determined to be incomplete or is denied (Gov. Code, § 66317, subd. (d)(1)). • Specifies that an ADU or JADU that contains less than 500 square feet of interior livable space does not increase assessable space (Gov. Code, § 66311, subds. (d)). This is important to the calculation and imposition of school fees. • Revises size limitations to be based on the square footage of interior living space of the ADU (Gov. Code, § 66321, subds. (b)(2)(A), (b)(2)(B), and (b)(3)). • Specifies the number of allowable ADUs described under Government Code section 66323 per lot (Gov. Code, § 66323, subd. (a)).
• Clarifies that fire sprinklers are not required for a JADU if the primary residence does not have fire sprinklers and that the addition of a JADU cannot trigger the requirement for fire sprinklers (Gov. Code, § 66323, subd. (d)). • Adds section 66333.5, which specifies that if a local agency fails to submit an adopted JADU ordinance to HCD within the 60-day timeline or fails to respond to HCD’s findings regarding their ordinance within the 30-day timeline, that ordinance is null and void and the local agency must only apply State ADU Law when processing applications for JADUs.
AB 462
AB 462 (Chapter 491, Statutes of 2025) made various changes to State ADU Law (Gov. Code, §§ 66328 and 66329) regarding requirements for the issuance of a certificate of occupancy during a declared state of emergency and creating an exception in coastal jurisdictions. This bill went into effect on October 10, 2025, as an urgency bill. This bill:
• Requires a local agency to issue a certificate of occupancy for an ADU constructed in a county that is subject to a proclamation of a state of emergency made by the Governor on or after February 1, 2025, even if the primary dwelling has not yet been issued a certificate of occupancy, if certain requirements are met, including that the primary dwelling was substantially damaged or destroyed by an event referenced in the state of emergency proclamation (Gov. Code, § 66328).
• Clarifies application processing when in a coastal zone by requiring a local government or the Coastal Commission, as specified, to either approve or deny a coastal development permit application for an ADU within 60 days of receiving a completed application (Gov. Code, § 66329, subd. (a)).
AB 130
AB 130 (Chapter 22, Statutes of 2025) made changes to the Civil Code and State ADU Law (Gov. Code, § 66323) regarding ADUs and went into effect on June 30, 2025. This bill:
• Specifies that reasonable restrictions in covenants, restrictions, and conditions, as described in the Civil Code, shall not include any fees or other financial requirements (Civil Code, § 714.3, subd. (b)).
• Removes Government Code section 66323, subdivision (g), which allowed the imposition of objective standards on ADUs in multifamily dwelling structures if the local agency had adopted an ADU ordinance by July 1, 2018.
AB 2533
AB 2533 (Chapter 834, Statutes of 2024) made various changes to State ADU Law (Gov. Code, § 66311.7) regarding unpermitted ADUs and went into effect on January 1, 2025. This bill:
• Prohibits a local agency from denying a permit for an unpermitted ADU or JADU that was constructed before January 1, 2020, for building code violations, unless the local agency makes a finding that correcting the violation is necessary to comply with conditions that would otherwise deem a building substandard.
• Requires a local agency to inform the public about the provisions prohibiting denial of a permit for an unpermitted ADU or JADU.
• Requires this information to include a checklist of the conditions that deem a building substandard and to inform homeowners that, before submitting a permit application, the homeowner may obtain a confidential third-party code inspection from a licensed contractor.
• Prohibits a local agency from requiring a homeowner to pay impact fees or connection or capacity charges except under specified circumstances. • Authorizes an inspector from a local agency, upon receiving an application for a permit for a previously unpermitted ADU or JADU constructed before January 1, 2020, to inspect the unit for compliance with health and safety standards and provide recommendations to comply with health and safety standards.
• Prohibits the local agency from penalizing an applicant for having the unpermitted ADU and would require the local agency to approve necessary permits to correct noncompliance with health and safety standards.
SB 1211
SB 1211 (Chapter 296, Statutes of 2024) made various changes to State ADU Law (Gov. Code, §§ 66313, 66314, 66323) with regard to replacement parking and 66323 Units on lots with existing or proposed multifamily dwellings and went into effect on January 1, 2025. This bill:
• Defines “livable space” as a space in a dwelling intended for human habitation, as the term appears in Government Code sections 66313, subdivision (e), and 66323, subdivision (a)(3)(A).
• Specifies that uncovered, off-street parking spaces demolished in conjunction with the construction of an ADU do not need to be replaced. • Authorizes up to eight detached ADUs on a lot with an existing multifamily dwelling, provided that the number of ADUs does not exceed the number of existing units on the lot.
• Prohibits a local agency from imposing any objective development standards on 66323 Units that are not authorized by the provisions of Government Code section 66323, subdivision (a).
SB 477
SB 477 (Chapter 7, Statutes of 2024) made changes to the numbering of the sections of Government Code for State ADU and JADU Laws. The bill went into effect on March 25, 2024.
AB 976 and AB 1033
AB 976 (Chapter 751, Statutes of 2023) and AB 1033 (Chapter 752, Statutes of 2023) made changes to State ADU Law (Gov. Code, §§ 66310-66342) regarding the occupancy, sale, and separate conveyance of ADUs and went into effect on January 1, 2024. These bills:
• Removed the existing 2025 sunset prohibition on a local agency imposing an owner occupancy requirement on any ADU and would instead prohibit a local agency from requiring owner-occupancy for an ADU (Gov. Code, § 66315). • Authorized a local agency to adopt a local ordinance to allow the separate conveyance of the primary dwelling unit and ADU(s) as condominiums, subject to certain conditions (Gov. Code, §§ 66340-66342). Specifically:
• Condominiums shall be created pursuant to the Davis-Stirling Common Interest Development Act.
• Condominiums shall be created in conformance with the Subdivision Map Act.
• Requires a safety inspection of the ADU prior to recordation of the condominium plan.
• Requires lienholders’ consent prior to recordation of the subdivision map or condominium plan.
• The local agency shall provide notice to consumers regarding requirements, establishment of condominium, and lienholder consent. • Requires homeowner notice to utilities.
• The owner of a separate interest in an existing planned development must obtain express written authorization from the association.
AB 1332
AB 1332 (Chapter 759, Statutes of 2023) added section 65852.27 to the Government Code to expedite the approval of ADUs and went into effect on January 1, 2024. This bill:
• Requires the local agency to develop a program for the preapproval of ADU plans by January 1, 2025.
• Requires the local agency to accept ADU plan submissions for preapproval from any party and approve or deny applications pursuant to standards established in Government Code sections 66314-66342.
• Requires the local agency to post preapproved ADU plans and the contact information of the applicant on the local agency’s internet website. • Allows the local agency to also post plans pre-approved by other local or state agencies.
• Authorizes a local agency to charge a fee to an applicant for the preapproval of an ADU plan.
• Requires a local agency to approve or deny within 30 days an application for a detached ADU that utilizes either a plan preapproved by the local agency or another agency within the state, or a plan that is identical to a plan in a previously approved application for a detached ADU. The plans must be valid within the current triennial California Building Standards Code rulemaking cycle.
AB 434
AB 434 (Chapter 740, Statutes of 2023) modified amended Government Code section 65585, subdivision (j), by adding State ADU Law (Gov. Code, §§ 66310- 66342) and SB 9 (Gov. Code, §§ 65852.21, 66411.7), among others, to the list of laws that HCD is authorized to enforce, including HCD’s authority to notify a city, county, city and county, or the Attorney General when the planning agency of a city, county, or city and county fails to comply with those laws. The bill went into effect on January 1, 2024.