AB 2127
Accessory dwelling units: private sewage disposal systems.
Vote required
Majority
Fiscal committee
No
Appropriation
No
Current location
Housing
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Bill overview
This bill changes regulations around accessory dwelling units (ADUs) in California, particularly concerning private sewage disposal systems. It prohibits local agencies from denying ADU approval solely because a property uses a private sewage system, as long as the system meets state standards. The bill also prevents health officers from requiring minimum lot size requirements based on sewage systems and prohibits installing new systems unless absolutely necessary. It clarifies parking requirements and streamlines the approval process for existing systems.
Key provisions
- Local agencies cannot prohibit ADUs due to private sewage systems meeting state standards.
- Health officers cannot withhold approval based on minimum lot size requirements for private sewage systems.
- Local agencies cannot require new or alternative sewage systems unless there's a risk to public health or water quality.
- Parking requirements for ADUs are limited to one space per unit or bedroom.
- Existing off-street parking spaces don't need to be replaced when a garage is demolished for an ADU.
- Fire sprinkler requirements for ADUs are not triggered by the demolition of a garage.
- The bill clarifies that ADUs do not increase density beyond existing allowances.
- Local agencies cannot require notice or placards for garage demolitions related to ADU construction (except in historic districts).
Who is affected
- Homeowners
- Local governments (cities and counties)
- Real estate developers
Arguments in favor
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AB2127:v96#DOCUMENT
Bill Start
| Amended IN Senate June 08, 2026 |
| Amended IN Assembly April 06, 2026 |
| Amended IN Assembly March 19, 2026 |
CALIFORNIA LEGISLATURE— 2025–2026 REGULAR SESSION
Assembly Bill
No. 2127
| Introduced by Assembly Member Johnson (Coauthor: Assembly Member Patterson) |
| February 18, 2026 |
An act to amend Section 66314 of the Government Code, relating to land use.
LEGISLATIVE COUNSEL'S DIGEST
AB 2127, as amended, Johnson. Accessory dwelling units: private sewage disposal systems.
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 in accordance with specified standards and conditions. Existing law requires the ordinance, if adopted, to meet certain requirements, including designating areas within the jurisdiction where accessory dwelling units may be permitted. Existing law authorizes the designation of areas to be based on the adequacy of water and sewer services and the impact of accessory dwelling units on traffic flow and public safety. Existing law also requires the ordinance to require approval by the local health officer where a private sewage disposal system is being used, if required.
This bill would prohibit a local agency from prohibiting an accessory dwelling unit in an area solely because the lots are served by private sewage disposal systems. The bill would prohibit a local health officer from withholding approval based on a minimum lot size requirement if the private sewage disposal system meets certain operating requirements established by the State Water Resources Control Board and the regional water quality control board for that lot size, and as provided. The bill would prohibit the local health officer from requiring the installation of a new or alternative system as a condition of approval if the local health officer determines that an existing private sewage disposal system is verified to be functioning properly and has the capacity to serve the additional load of an accessory dwelling unit, as provided, and except as specified. By imposing new duties on local agencies relating to the approval of accessory dwelling units, the 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.
Digest Key
Vote: MAJORITY Appropriation: NO Fiscal Committee: YES Local Program: YES
Bill Text
The people of the State of California do enact as follows:
SECTION 1.
Section 66314 of the Government Code is amended to read:
66314.
A local agency may, by ordinance, provide for the creation of accessory dwelling units in areas zoned to allow single-family or multifamily dwelling residential use. The ordinance shall do all of the following:
(a) (1) Designate areas within the jurisdiction of the local agency where accessory dwelling units may be permitted. The designation of areas may be based on the adequacy of water and sewer services and the impact of accessory dwelling units on traffic flow and public safety. A local agency that does not provide water or sewer services shall consult with the local water or sewer service provider regarding the adequacy of water and sewer services before designating an area where accessory dwelling units may be permitted.
(2) Notwithstanding paragraph (1), a local agency shall not prohibit an accessory dwelling unit in an area solely because the lots are served by private sewage disposal systems rather than by a public sewer system.
(b) (1) Impose objective standards on accessory dwelling units that include, but are not limited to, parking, height, setback, landscape, architectural review, maximum size of a unit, and standards that prevent adverse impacts on any real property that is listed in the California Register of Historical Resources. These standards shall not include requirements on minimum lot size.
(2) Notwithstanding paragraph (1), a local agency may reduce or eliminate parking requirements for any accessory dwelling unit located within its jurisdiction.
(c) Provide that accessory dwelling units do not exceed the allowable density for the lot upon which the accessory dwelling unit is located, and that accessory dwelling units are a residential use that is consistent with the existing general plan and zoning designation for the lot.
(d) Require the accessory dwelling units to comply with all of the following:
(1) Except as provided in Article 4 (commencing with Section 66340), the accessory dwelling unit may be rented separate from the primary residence, but shall not be sold or otherwise conveyed separate from the primary residence.
(2) The lot is zoned to allow single-family or multifamily dwelling residential use and includes a proposed or existing dwelling.
(3) The accessory dwelling unit is either attached to, or located within, the proposed or existing primary dwelling, including attached garages, storage areas or similar uses, or an accessory structure or detached from the proposed or existing primary dwelling and located on the same lot as the proposed or existing primary dwelling, including detached garages.
(4) If there is an existing primary dwelling, the total floor area of an attached accessory dwelling unit shall not exceed 50 percent of the existing primary dwelling.
(5) The total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet.
(6) No passageway shall be required in conjunction with the construction of an accessory dwelling unit.
(7) No setback shall be required for an existing living area or accessory structure or a structure constructed in the same location and to the same dimensions as an existing structure that is converted to an accessory dwelling unit or to a portion of an accessory dwelling unit, and a setback of no more than four feet from the side and rear lot lines shall be required for an accessory dwelling unit that is not converted from an existing structure or a new structure constructed in the same location and to the same dimensions as an existing structure.
(8) Local building code requirements that apply to detached dwellings, except that the construction of an accessory dwelling unit shall not constitute a Group R occupancy change under the local building code, as described in Section 310 of the California Building Code (Title 24 of the California Code of Regulations), unless the building official or enforcement agency of the local agency makes a written finding based on substantial evidence in the record that the construction of the accessory dwelling unit could have a specific, adverse impact on public health and safety. Nothing in this paragraph shall be interpreted to prevent a local agency from changing the occupancy code of a space that was uninhabitable space or was only permitted for nonresidential use and was subsequently converted for residential use pursuant to this article.
(9) (A)Approval by the local health officer where a private sewage disposal system is being used, if required. The
(A) The local health officer shall not withhold approval based on a minimum lot size requirement if the private sewage disposal system meets the operating requirements established by the State Water Resources Control Board pursuant to Section 13291 of the Water Code Code, including the local agency management program approved by the regional water quality control board, for that lot size.
(B) If the local health officer determines that an existing private sewage disposal system is verified to be functioning properly and has the capacity to serve the additional load of an accessory dwelling unit, as determined by a qualified professional, based on the operating requirements established by the State Water Resources Control Board pursuant to Section 13291 of the Water Code for that lot size, pursuant to the operating requirements described in subparagraph (A), the local health officer shall not require the installation of a new or alternative system as a condition of approval, unless there is specific, substantial evidence that the existing system creates a present approving the accessory dwelling unit would create a risk to public health or water quality.
(10) (A) Parking requirements for accessory dwelling units shall not exceed one parking space per accessory dwelling unit or per bedroom, whichever is less. These spaces may be provided as tandem parking on a driveway.
(B) Offstreet parking shall be permitted in setback areas in locations determined by the local agency or through tandem parking, unless specific findings are made that parking in setback areas or tandem parking is not feasible based upon specific site or regional topographical or fire and life safety conditions.
(C) This subparagraph shall not apply to an accessory dwelling unit that is described in Section 66322.
(11) When a garage, carport, covered parking structure, or uncovered parking space is demolished in conjunction with the construction of an accessory dwelling unit or converted to an accessory dwelling unit, the local agency shall not require that those offstreet parking spaces be replaced.
(12) Accessory dwelling units shall not be required to provide fire sprinklers if they are not required for the primary residence. The construction of an accessory dwelling unit shall not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling.
(e) Require that a demolition permit for a detached garage that is to be replaced with an accessory dwelling unit be reviewed with the application for the accessory dwelling unit and issued at the same time.
(f) An accessory dwelling unit ordinance shall not require, and the applicant shall not be otherwise required, to provide written notice or post a placard for the demolition of a detached garage that is to be replaced with an accessory dwelling unit, unless the property is located within an architecturally and historically significant historic district.
SEC. 2.
No reimbursement is required by this act pursuant to Section 6 of Article XIII B of the California Constitution because a local agency or school district has the authority to levy service charges, fees, or assessments sufficient to pay for the program or level of service mandated by this act, within the meaning of Section 17556 of the Government Code.