SB 897 Explained: ADU Height, Permit Timeline, and JADUs

California’s SB 897, signed by Governor Gavin Newsom on September 28, 2022, and effective January 1, 2023, rewrote several of the rules governing Accessory Dwelling Units and Junior Accessory Dwelling Units. The law raised height limits for ADUs, put local agencies on a 60-day clock to approve or deny applications, barred denials based on existing nonconforming zoning or unpermitted structures that aren’t a safety problem, and removed building code triggers that had been used to block or slow ADU projects. Authored by Senator Bob Wieckowski and sponsored by the Bay Area Council, it sits alongside AB 2221 as the pair of 2022 bills that reshaped the state’s ADU framework.¹

How Tall Your ADU Can Be

Before SB 897, cities and counties could cap detached ADUs at 16 feet. The law created a tiered set of height floors that local agencies cannot go below:

Detached ADUs: 16 feet as the base.
Detached ADUs within a half-mile walking distance of a major transit stop or high-quality transit corridor, or on a lot with an existing or proposed multistory, multifamily dwelling: 18 feet.²
Attached ADUs: up to 25 feet, or the height limit for the primary dwelling, whichever is lower. Local agencies are not required to allow more than two stories.²
An additional two feet is allowed so the ADU’s roof pitch can match the primary dwelling.²

The 60-Day Permit Clock

Local agencies must approve or deny a completed ADU or JADU application within 60 days. If an agency misses that window and has not adopted a compliant local ADU ordinance, the application is deemed approved by operation of law.³ A denial is not a one-line rejection: the agency has to issue a written list of specific deficiencies and tell you how to fix each one.⁴

Agencies are also limited to “objective standards” when reviewing applications. The law defines those as standards involving no personal or subjective judgment by a public official and that are uniformly verifiable against an external benchmark.² Design and aesthetic judgments that can’t be measured don’t qualify.

Nonconforming Conditions and Unpermitted Structures Can’t Block Your ADU

SB 897 shut off a common denial path. A local agency cannot deny an ADU or JADU permit because of nonconforming zoning conditions, building code violations, or unpermitted structures already on the property, so long as those issues don’t threaten public health and safety and aren’t affected by the new construction.¹

There’s a specific amnesty for older unpermitted ADUs. For units built before January 1, 2018, local agencies cannot deny a building permit based on building standard violations unless correcting them is specifically necessary to protect the health and safety of occupants or the public. Buildings already deemed substandard under the State Housing Law are excluded.¹ A later bill, AB 2533 (2024), pushed that cutoff forward to January 1, 2020.⁵

Replacing a detached garage with an ADU got easier too. The demolition permit must be reviewed and issued together with the ADU building permit, and no public placards or written demolition notices are required unless the property sits in an architecturally or historically significant district.⁴

Building Code, Occupancy, and Sprinklers

One technical fix in SB 897 has outsized practical effect. Constructing an ADU does not count as a “Group R” occupancy change under the building code. That blocks local agencies from reclassifying a residential structure just because an ADU was added, which would otherwise trigger extra building standards and compliance costs.⁴ A building official can override this exemption only by issuing express written findings that the ADU construction could result in a specific, adverse impact on public health and safety.¹

The law also prohibits agencies from requiring fire sprinkler installation in your existing primary residence as a condition of building the ADU.⁴

Setbacks, Parking, and Garage Conversions

Front setback rules cannot be used to prevent an 800-square-foot ADU if there is no alternative site on the lot where it could be built while keeping four-foot side and rear setbacks.¹ For existing multifamily buildings whose side or rear setbacks are already under four feet, local agencies cannot force modifications to the existing building as a condition of ADU approval, and cannot reject the ADU application because the existing structure doesn’t meet current setback or height standards.⁶

On parking, no parking requirement can be imposed on an ADU when its application is submitted alongside a new single-family dwelling. For new multifamily projects, local agencies must reduce the required parking by two spaces for each detached ADU proposed on the same lot.⁴

Conversions of existing structures like garages or accessory buildings are approved ministerially and are exempt from many local zoning and design standards. They must keep setbacks adequate for fire and safety, but the standard four-foot side and rear setback requirement doesn’t apply. A converted accessory structure is also eligible for a 150-square-foot expansion to accommodate features like stairwells needed for ingress and egress.²

Impact Fees and Minimum Size

Local agencies cannot charge impact fees on an ADU smaller than 750 square feet. For an ADU 750 square feet or larger, any impact fee must be proportionate to the size of the primary residence.³ Utility connection and capacity charges are handled separately and are not treated as impact fees under the law.²

Agencies also cannot set minimum or maximum size requirements, or a size tied to a percentage of the primary dwelling, if doing so would prevent construction of at least an 800-square-foot ADU with four-foot side and rear setbacks.²

What Changed for Junior ADUs

A JADU is a small unit of no more than 500 square feet contained within a single-family residence. SB 897 clarified that enclosed uses within a residence, including attached garages, count as part of the single-family residence for purposes of JADU construction.⁷ It also extended JADU construction to attachments on a detached ADU or on a garage attached to the primary residence, and required that a JADU attached to an ADU have a separate entrance.⁴

A JADU without its own bathroom needs a separate entrance from the main entrance of the structure and an interior entry to the main living area. JADU applications ride the same 60-day clock as ADU applications, and the same protection against denials based on nonconforming conditions or unpermitted structures applies unless those conditions threaten health or safety.²

How SB 897 Fits With the Current ADU Rules

SB 897 is one layer in a stack of statutes. If you’re planning an ADU now, several later bills modify what it set up:

AB 976 (2023) permanently removed owner-occupancy requirements for ADUs, eliminating a sunset that had been set for 2025.²
AB 1033 (2023) authorizes local agencies to adopt ordinances allowing the separate sale of a primary dwelling and its ADU as condominiums. SB 897 did not address separate sale.²
SB 477 (2024) recodified the ADU statutes, moving them from their earlier Government Code locations to sections 66310 through 66342.⁸
SB 1211 (2024) raised the number of detached ADUs allowed on lots with existing multifamily dwellings from two to as many as eight, capped at the total number of existing units on the lot, and prohibited agencies from requiring replacement parking when uncovered spaces are demolished for ADU construction.⁵
AB 2533 (2024) moved the amnesty cutoff for legalizing unpermitted ADUs from January 1, 2018, to January 1, 2020, and added new public notification requirements about the legalization process.⁵

If a local ordinance conflicts with the state ADU statutes, the state law controls and the conflicting ordinance is null and void. As of January 1, 2024, the California Department of Housing and Community Development has statutory authority to enforce all state ADU laws, and its Housing Accountability Unit can refer local violations to the California Attorney General.² If your city is applying a rule that doesn’t match what SB 897 and its successors say, that enforcement channel is where complaints go.

1
Best Best & Krieger LLP. Two New Bills Further Restrict Local Regulation of ADUs
2
California Department of Housing and Community Development. ADU Handbook
3
City of Foster City. Housing Legislation
4
California State Assembly. SB 897 Assembly Committee on Local Government Analysis
5
Best Best & Krieger LLP. Governor Newsom Signs Three New Accessory Dwelling Unit Bills
6
FindHOALaw. SB 897 Accessory Dwelling Units
7
California Legislature. SB 897 Bill Page
8
City of Los Angeles. ZA Memorandum No. 143