SB 897 is the California law that made it easier to add an ADU from January 1, 2023. It set taller minimum height limits, stopped cities from denying an ADU because of unrelated old code problems or unpermitted structures, opened a path to permit many ADUs built before 2018, and confirmed that an ADU does not trigger fire sprinklers in the main house.
This guide explains, in plain English, what SB 897 actually changed, what it did not change, and which newer ADU laws matter for San Diego homeowners in 2026. NJ Design & Build is a design-build ADU contractor in San Diego, and we use these rules on every ADU we plan and permit.
What is SB 897?
SB 897 is a California Senate bill, signed in 2022, that amended the state’s accessory dwelling unit (ADU) law. It was passed alongside AB 2221, and both took effect on January 1, 2023. Together they closed loopholes that some cities used to slow ADUs down, and they made the rules for height, setbacks, older structures and permit decisions clearer.
What did SB 897 change for ADUs?
Taller ADUs are allowed
Before 2023 many cities capped ADUs at 16 feet. The new minimum height limits are:
- Detached ADU within half a mile walking distance of a major transit stop or high-quality transit corridor: at least 18 feet, plus up to 2 more feet to match the roof pitch of the main house.
- Detached ADU on a lot with an existing or proposed multifamily, multistory building: at least 18 feet.
- Attached ADU: at least 25 feet, or the local height limit for the zone if that is lower. A city can still limit it to two stories.
No forced fixes to unrelated problems
A city cannot deny your ADU because you would have to correct nonconforming zoning conditions, building code violations or unpermitted structures that don’t threaten health or safety and aren’t affected by the ADU. That includes old issues on the main house. Corrections can still be required where they are needed to protect health and safety.
A path to permit older unpermitted ADUs
If an ADU was built without a permit before January 1, 2018, the city cannot deny a building permit for it just because it doesn’t meet current building standards or ADU rules – unless a fix is needed to protect the health and safety of the people living there or the public, or the building is substandard under the State Housing Law.
No fire sprinklers triggered in the main house
Adding an ADU does not trigger a requirement to add fire sprinklers to your existing home.
Front setbacks can’t block a modest ADU
Front setback rules cannot be used to stop an ADU of up to 800 square feet that meets the height limits and has 4-foot side and rear setbacks, where there is no other place to put it.
Clearer permit decisions
ADU rules must be objective – no subjective judgment by an official. If a city denies an ADU or JADU application, it must give you a full list of what is missing or deficient and how to fix it, within the 60-day review period. Replacing a detached garage with an ADU needs a demolition permit, which must be issued at the same time as the ADU permit.
What SB 897 did not change
Some older articles credit SB 897 with changes that actually came from other laws. Here is the accurate picture:
- Impact fees: the exemption for smaller ADUs comes from earlier ADU laws. From January 1, 2026, SB 543 says no development impact fees can be charged on an ADU of 750 sq ft or less of interior livable space, and school impact fees are waived for ADUs of 500 sq ft or less.
- Owner occupancy: cities can no longer require you to live on the property to have an ADU – that change came from AB 976 in 2023, not SB 897.
- Lot splits and duplexes: these come from SB 9 (2021), a separate law with its own rules.
Which newer ADU laws matter in San Diego in 2026?
- SB 543 (from Jan 1, 2026): size limits are measured by interior livable space; cities must decide whether an application is complete within 15 business days and must offer a written appeal process.
- AB 1154 (from Jan 1, 2026): a junior ADU (JADU) only needs the owner to live on site if it shares a bathroom with the main house. JADUs, and some ADUs, must be rented for more than 30 days at a time.
- AB 462 (from Oct 10, 2025): for coastal properties, cities with a certified local coastal program must approve or deny an ADU coastal development permit within 60 days, and those permits can no longer be appealed to the California Coastal Commission – useful for many coastal San Diego neighborhoods.
For the City of San Diego’s own process, read our step-by-step guide to getting an ADU permit in San Diego and our latest San Diego ADU regulations update.
What SB 897 means for your San Diego ADU
- If your property has an old unpermitted patio cover, shed or garage conversion that isn’t affected by the ADU and isn’t a safety risk, it shouldn’t block your new ADU.
- If you already have an ADU built before 2018 without permits, you may be able to legalize it – an inspection shows what must be fixed.
- If you are near transit or want an attached ADU, the higher height limits can make room for a loft or a second story.
- Budget is still the biggest question – see our 2026 ADU cost guide for San Diego for current ranges.
Plan your ADU with NJ Design & Build
Our design-build team handles the drawings, permits and construction under one contract, so state and city rules are checked before you spend money on plans. Learn more about our ADU builders in San Diego or book a free consultation.
This article is general information, not legal advice. ADU rules change and local details vary, so confirm your project with the City of San Diego Development Services Department or your local planning office. Last updated November 2026.
Frequently asked questions
When did SB 897 take effect?
SB 897 took effect on January 1, 2023. It was passed together with AB 2221, and both bills updated California’s statewide ADU rules at the same time.
Can my city make me fix old code problems before I add an ADU?
Generally no. Under SB 897, a city cannot deny your ADU because of nonconforming zoning conditions, building code violations or unpermitted structures that don’t threaten health or safety and aren’t affected by the ADU. Fixes are still required where health and safety are at risk.
Can I legalize an unpermitted ADU in San Diego?
Often, yes. For an unpermitted ADU built before January 1, 2018, a city cannot deny the building permit just because of building standard violations or ADU-law issues, unless a correction is needed for health and safety or the building is substandard. An inspection will show what has to be fixed.
Does adding an ADU mean I need fire sprinklers in my main house?
No. Building an ADU does not trigger a fire sprinkler requirement for the existing main house.
Did SB 897 remove ADU impact fees and owner-occupancy rules?
No – those came from other laws. The impact fee exemption for smaller ADUs comes from earlier ADU laws and, from 2026, SB 543 measures the 750 sq ft limit by interior livable space. Owner-occupancy rules for ADUs were removed by a separate 2023 law, AB 976.
