California’s 2025 ADU Legislation: What Local Agencies Need to Know
February 5, 2026If you’re feeling a little whiplash from the constant revisions to ADU laws, you’re not alone. Since the state embarked on its mission to boost housing production through ADUs, each year has brought a slate of new bills. The incentives and streamlining seem to be working; many California cities have seen a measurable uptick in ADU applications year over year, and CA YIMBY reports that ADU permits in California increased by 15,334% between 2016 and 2022.
The good news? The 2025 legislative session brought us only four ADU bills and the changes are refinements rather than overhauls. The less-good news? Local agencies still need to update their processes, train staff, and possibly revise ordinances to ensure they’re not in conflict with State statutes. Here’s what the 2025 legislative session delivered:
The Emergency Response: AB 462
AB 462 (Lowenthal) tackles two distinct issues, though one is far more time-sensitive than the other. First, the bill addresses the aftermath of Governor-declared emergencies, creating a pathway for ADUs to receive certificates of occupancy even when the primary dwelling on the property hasn’t been rebuilt yet. This provision applies to counties subject to emergency proclamations issued on or after February 1, 2025. The bill was inspired by the challenges faced by homeowners impacted by the devastating fires in Altadena and Pacific Palisades. Since the Governor’s Los Angeles County proclamation was issued on January 7, 2025, the bill is not applicable there, but will be helpful to other communities in the future.
The bill’s second provision tackles ADUs in the Coastal Zone, requiring that coastal development permit applications for ADUs be approved or denied within 60 days of receiving a complete application. This timeline mirrors the existing ministerial review period for standard ADUs, extending that expedited approach to the coastal context. Local governments in the coastal zone will need to coordinate their ADU approval process with their coastal permitting process, ensuring both happen concurrently.
JADUs Get More Flexible: AB 1154
JADUs are limited to 500 square feet and carved out of existing (or proposed) single-family homes. One of their defining features has been a strict owner-occupancy requirement, which has limited their appeal and utility. AB 1154 (Carrillo) loosens that requirement so that the owner-occupancy mandate will only apply to JADUs that share sanitation facilities with the main house. If the JADU has its own bathroom, the property owner can live elsewhere. For homeowners, it means JADUs become a more viable investment. For local agencies, it means JADU ordinances may need revisions to reflect this new flexibility. The bill also adds a minimum 30-day rental term requirement aimed at preventing JADUs from becoming short-term rentals, keeping them in the long-term housing supply where the state (and likely, the local agency) wants them.
Enforcement with Teeth: SB 9
SB 9 (not to be confused with the 2021 lot-split bill of the same number), authored by Senator Arreguín, addresses a longstanding gap in the ADU ordinance review process. Current law requires local agencies to submit their ADU ordinances to HCD within 60 days of adoption, and HCD can issue findings of noncompliance. Until now, there wasn’t a clear consequence for agencies that simply ignored HCD’s feedback or never submitted their ordinances in the first place. SB 9 fixes that. If a local agency does not submit their ordinance to HCD within 60 days of adoption, or doesn’t respond to HCD’s noncompliance findings within 30 days, the ordinance is null and void. Just like that, local standards disappear, and State default standards kick in. HCD’s message here is to submit your ordinances on time, take HCD’s review seriously, and respond promptly to any concerns.
The Big Cleanup: SB 543
Authored by Senator McNerney, this bill is the legislative equivalent of your annual zoning code cleanup: lots of small fixes, clarifications, and conforming changes. Here are the highlights:
- Measurement clarity: ADU and JADU square footage measurements now refer to “interior livable space” to describe what constitutes accessory square footage.
- Application completeness: Agencies now have just 15 business days to review an ADU or JADU application and determine whether it’s complete. If it’s not, a specific list of what’s missing and how to fix it must be provided to the applicant. There must also be an appeals process if a local agency determines an application is incomplete or denies a permit.
- Fee proportionality: The bill prohibits any impact fees on ADUs with 750 square feet or less of interior livable space (and JADUs with 500 square feet or less). For larger ADUs, fees must be charged proportionately based on square footage relative to the primary dwelling.
- JADU parity: Provisions that previously applied only to ADUs are now extended to JADUs. This includes rules about fire sprinklers, ministerial approval processes, and HCD review of ordinances.
- Number of units permitted: Perhaps most significantly, this bill clarifies a point that many agencies disputed with HCD: what combination of ADUs/JADUs is required by State law on a single lot. SB 543 now clearly states that agencies must ministerially approve the following on single-family properties: one internal ADU, one internal JADU (with up to 150 square feet of expansion for access), and one detached new-construction ADU of up to 800 square feet. The previous statutory language was ambiguous and this bill is not.
Now what?!
Keeping up with ADU legislation can be exhausting and time consuming. Every year brings new requirements, new timelines, and new (sometimes nuanced) rules. By the time planning staff is trained on the latest changes, the next legislative session is underway.
For 2026, key local code updates should include:
- Review ADU and JADU ordinances to ensure they comply with the new requirements, particularly the measurement standards, fee provisions, and combination of accessory units allowed by SB 543.
- Update application review procedures to meet the 15-day completeness determination requirement and establish the required appeals process.
- Train staff on the new coastal permitting timelines if in the coastal zone, and develop emergency protocols for post-disaster ADU approvals (which hopefully won’t be needed).
- Submit any new or revised ordinances to HCD promptly and address feedback promptly.
- Revisit your fee schedules to ensure compliance with the refined impact fee rules.
The legislative trend with ADUs and JADUs continues to be more streamlining, more accountability, and less local discretion. Most of this year’s changes are logical refinements that address real-world problems and are not radical departures from existing law. Besides who knows? Maybe in a few years, the annual ADU bill parade will slow down. But until then, welcome to 2026! Time to update your ADU ordinance again.
Questions about how these changes apply to your jurisdiction? Contact Urban Planner Kristi Bascom.