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SB-543 • 2026

Accessory dwelling units and junior accessory dwelling units.

Accessory dwelling units and junior accessory dwelling units.

Education Housing Land
Enacted

This bill passed the Legislature and reached final enactment based on the latest official action.

Sponsor
McNerney
Last action
2025-10-10
Official status
Chaptered by Secretary of State. Chapter 520, Statutes of 2025.
Effective date
Not listed

Plain English Breakdown

The bill summary and text do not provide specific information on enforcement mechanisms or consequences for non-compliance beyond nullifying ordinances. The effective date is also unspecified in the provided official source material.

Rules for Small Homes in Big Houses

This law changes rules about small homes (called JADUs) that can be built inside bigger houses and sets guidelines to make sure these homes are easy to build.

What This Bill Does

  • Changes the definition of a junior accessory dwelling unit (JADU) to require it to be no more than 500 square feet in interior livable space.
  • Requires local agencies to send new rules about JADUs to the state housing department for review within 60 days after making them.
  • Nullifies and voids a JADU ordinance if the local agency fails to submit it or respond to findings that the ordinance is noncompliant with requirements.
  • Ensures that permit applications for JADUs are considered ministerially by local agencies, unless a JADU ordinance exists.
  • Limits fees and charges on small homes built inside bigger houses to make it easier and cheaper to build them.

Who It Names or Affects

  • People who want to add a small home (JADU) in their existing house.
  • Local government officials who create rules for building permits.
  • State housing department that reviews local rules about JADUs.

Terms To Know

Junior accessory dwelling unit (JADU)
A small home built inside a bigger house, usually no more than 500 square feet in interior livable space.
Accessory dwelling unit (ADU)
A separate living space on the same property as a main house, like a garage apartment or backyard cottage.

Limits and Unknowns

  • The bill does not specify an effective date for when these changes will start.
  • It is unclear how many local agencies will need to change their rules based on this new law.

Bill History

  1. 2025-10-10 California Legislative Information

    Chaptered by Secretary of State. Chapter 520, Statutes of 2025.

  2. 2025-10-10 California Legislative Information

    Approved by the Governor.

  3. 2025-09-09 California Legislative Information

    Enrolled and presented to the Governor at 2 p.m.

  4. 2025-09-02 California Legislative Information

    Assembly amendments concurred in. (Ayes 40. Noes 0. Page 2408.) Ordered to engrossing and enrolling.

  5. 2025-08-28 California Legislative Information

    In Senate. Concurrence in Assembly amendments pending.

  6. 2025-08-28 California Legislative Information

    Read third time. Passed. (Ayes 75. Noes 0. Page 2773.) Ordered to the Senate.

  7. 2025-08-21 California Legislative Information

    Read second time. Ordered to third reading.

  8. 2025-08-20 California Legislative Information

    From committee: Do pass. (Ayes 15. Noes 0.) (August 20).

  9. 2025-07-17 California Legislative Information

    From committee: Do pass and re-refer to Com. on APPR. (Ayes 10. Noes 0.) (July 16). Re-referred to Com. on APPR.

  10. 2025-07-08 California Legislative Information

    From committee with author's amendments. Read second time and amended. Re-referred to Com. on L. GOV.

  11. 2025-06-19 California Legislative Information

    Read second time and amended. Re-referred to Com. on L. GOV.

  12. 2025-06-18 California Legislative Information

    From committee: Do pass as amended and re-refer to Com. on L. GOV. (Ayes 11. Noes 0.) (June 18).

  13. 2025-06-05 California Legislative Information

    Referred to Coms. on H. & C.D. and L. GOV.

  14. 2025-05-28 California Legislative Information

    In Assembly. Read first time. Held at Desk.

  15. 2025-05-27 California Legislative Information

    Read third time. Passed. (Ayes 39. Noes 0. Page 1250.) Ordered to the Assembly.

  16. 2025-05-13 California Legislative Information

    Read second time. Ordered to third reading.

  17. 2025-05-12 California Legislative Information

    From committee: Be ordered to second reading pursuant to Senate Rule 28.8.

  18. 2025-05-02 California Legislative Information

    Set for hearing May 12.

  19. 2025-04-30 California Legislative Information

    From committee: Do pass and re-refer to Com. on APPR. (Ayes 7. Noes 0. Page 968.) (April 30). Re-referred to Com. on APPR.

  20. 2025-04-23 California Legislative Information

    From committee with author's amendments. Read second time and amended. Re-referred to Com. on L. GOV.

  21. 2025-04-23 California Legislative Information

    From committee: Do pass and re-refer to Com. on L. GOV. (Ayes 11. Noes 0. Page 832.) (April 22). Re-referred to Com. on L. GOV.

  22. 2025-04-22 California Legislative Information

    Set for hearing April 30 in L. GOV. pending receipt.

  23. 2025-04-09 California Legislative Information

    From committee with author's amendments. Read second time and amended. Re-referred to Com. on HOUSING.

  24. 2025-04-04 California Legislative Information

    Set for hearing April 22.

  25. 2025-04-02 California Legislative Information

    Re-referred to Coms. on HOUSING and L. GOV.

  26. 2025-03-25 California Legislative Information

    From committee with author's amendments. Read second time and amended. Re-referred to Com. on RLS.

  27. 2025-03-05 California Legislative Information

    Referred to Com. on RLS.

  28. 2025-02-21 California Legislative Information

    From printer. May be acted upon on or after March 23.

  29. 2025-02-20 California Legislative Information

    Introduced. Read first time. To Com. on RLS. for assignment. To print.

Official Summary Text

SB 543, McNerney.
Accessory dwelling units and junior accessory dwelling units.
Existing law, the Planning and Zoning Law, among other things, provides for the creation by ordinance, or by ministerial approval if the local agency has not adopted an ordinance, of an accessory dwelling unit (ADU) or a junior accessory dwelling unit (JADU) in accordance with specified standards and conditions. Existing law defines the term “junior accessory dwelling unit” for these purposes to mean a unit that is no more than 500 square feet in size and contained entirely within a single-family structure.
This bill would revise 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.
Existing law makes certain declarations of the Legislature’s intent regarding the effect of an ADU ordinance. Existing law
authorizes the Department of Housing and Community Development to review, adopt, amend, or repeal guidelines to implement uniform standards or criteria that supplement or clarify the terms, references, and standards for an ADU.
This bill would revise the above-described declaration of legislative intent to additionally apply with respect to a JADU ordinance. The bill would also expand the department’s authority to review, adopt, amend, or repeal guidelines to additionally grant that authority with respect to terms, references, and standards for JADUs.
Existing law requires a local agency to submit an ADU ordinance to the Department of Housing and Community Development within 60 days after the adoption for department review, as specified. Under existing law, the standards applicable to an ADU under these provisions supersede a conflicting local ordinance, except as specified.
This
bill would similarly require a local agency to submit a JADU ordinance to the department within 60 days after adoption for department review and would require the department to notify the local agency if the ordinance is noncompliant with JADU ordinance requirements, as specified. The bill would nullify and void that ordinance if the local agency fails to submit a copy of that ordinance or respond to the department’s findings that the ordinance is noncompliant, as specified. The bill would also specify that the standards applicable to a JADU supersede any conflicting local ordinance, except as specified.
Existing law requires a local agency to consider ministerially a permit application for an ADU or a JADU within 60 days, as specified. If a local agency has not adopted an ADU ordinance, existing law requires a permit application for an ADU to be considered pursuant to this ministerial approval provision. Existing law prohibits a local ordinance, policy, or
regulation, other than an ADU ordinance consistent with the laws governing approvals of ADUs, from being the basis for the delay or denial of a building permit or a use permit under this ministerial approval provision.
If a local agency has not adopted a JADU ordinance, this bill would additionally require a permit application for a JADU to be considered pursuant to this ministerial approval provision, and would prohibit a local ordinance, policy, or regulation, other than a JADU ordinance consistent with the laws governing approvals of JADUs, from being the basis for the delay or denial of a building permit or a use permit under this ministerial approval provision. This bill would additionally require a permitting agency to determine whether an application for 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. If the permitting agency determines that an
application is incomplete, the bill would require 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 and authorize the applicant to cure and address the application, as specified. The bill would require the permitting agency, if a permit application is determined to be incomplete or is denied, to provide a process for the applicant to appeal that decision, as provided, and would require the permitting agency to provide a final written determination by not later than 60 business days after receipt of the written appeal.
Existing law imposes limits on construction, connection, and impact fees and capacity charges imposed on an ADU, including prohibiting impact fees upon the development of an ADU based on if the ADU is 750 square feet and requiring that any impact fee on an ADU of 750 square feet or more be charged proportionately in
relation to the square footage of the primary dwelling unit. Existing law prohibits a local agency, special district, or water corporation from requiring the applicant to install a new or separate utility connection between an ADU and the utility or imposing a related connection fee or capacity charge for specified ADUs, except as specified.
This bill would revise these provisions to additionally apply to construction, connection, and impact fees and capacity charges imposed on a JADU. The bill would revise the above-described limitation 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.
Existing law authorizes the governing board of a school district to levy a fee, charge, dedication, or other requirement against construction within the boundaries of the school district for the purpose of funding the construction or reconstruction of a school facility, subject to specified limitations. Under existing law, the fee, charge, dedication, or other requirement may only apply to specified constructions, including residential construction if the resulting assessable space exceeds 500 square feet.
This bill would specify that an ADU or a JADU that contains less than 500 square feet of interior livable space does not increase assessable space by 500 square feet under these provisions.
Existing law prohibits a local agency from establishing by ordinance a maximum square footage for an attached or detached ADU that is either less than 850 square feet or 1,000 square feet for an
ADU that provides more than one bedroom. Existing law also prohibits a local agency from establishing by ordinance any requirement for a zoning clearance or separate zoning review or any other minimum or maximum size for an ADU, size based upon a percentage of the proposed or existing primary dwelling, or limits on lot coverage, floor area ratio, open space, front setbacks, and minimum lot size, for attached or detached dwellings that does not permit at least an 800-square foot ADU with four-foot side and rear yard setbacks.
This bill would revise these size limitations to be based on the square feet of interior living space of the ADU.
Existing law requires a local agency to ministerially approve a building permit application within a residential or mixed-use zone for specified ADUs or JADUs, including one detached, new construction, ADU that does not exceed 4-foot side and rear yard setbacks for a lot with a proposed or
existing single-family dwelling. For these ADUs and JADUs, existing law authorizes a local agency to impose specified height limitations and total floor area limitations of no more than 800 square feet. Existing law prohibits a local agency from imposing a requirement that an ADU install a fire sprinkler if a sprinkler is not required for the primary residence.
This bill would require a local agency to ministerially approve a building permit application for a combination of the specified ADUs or JADUs and revise the total area limitation to be based on the square feet of interior livable space. The bill would revise the prohibition on requiring fire sprinkler installation, as described above, to additionally apply to a JADU.
This bill would make other technical and conforming changes to the provisions governing the review and approval of ADUs and JADUs.
By imposing additional
duties on local planning officials, this bill would impose a state-mandated local program.
The California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state. Statutory provisions establish procedures for making that reimbursement.
This bill would provide that no reimbursement is required by this act for a specified reason.

Current Bill Text

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