Why this matters: ADUs are a tool to build up housing inventory often slowed down by hesitant local agencies and unclear hurdles. Updated legislation enforces deadlines for local agencies to adopt ordinances to implement and keep ADU permits flowing.
No more waiting out the local clock
Before a homeowner can tackle a construction deadline, they first must deal with all the preplanning, zoning and administrative hoops politically embedded in local permit ordinances.
With Senate Bill 9 now law, local agencies have a new deadline to move ADUs plans forward, or the state codes take over.
Prior legislation required local agencies to adopt ordinances relating to an accessory dwelling unit (ADU) and submit them to the California Department of Housing and Community Development (HCD).
The submission to HCD is within 60 days of adopting the ordinance. The submission prompts the HCD to return their written findings about deficiencies in the ordinances to comply with state legislation. [GOV §66326(a)]
Problems with implementation arose as many local agencies simply failed to submit their newly adopted ordinances to HCD.
As of January 1, 2026, when local agencies do not submit new ordinances within 60 days of adoption or fail to respond to HCD deficiency notice of non-compliance within 30 days, the local ordinance, either way, is flat out void. [GOV §66326(d)]
Once the voided ordinance is no longer enforceable by local agencies, ADUs are managed by owners and contractors based on the standards set by California Government Code, not a reactionary local ordinance. This approval process circumventing the local authorities stands until the local agency adopts what the state determines is a compliant ordinance. [GOV §66326(d)]
Related article:
Letter of the superseding law
The state code as amended builds on previous legislation laying down the fundamental rules for ADU’s.
Before a local ordinance is in compliance, local agencies are tasked with applying standards on ADUs based on relevant limits such as:
- water and sewer services;
- parking;
- size;
- setback;
- density;
- landscape; and
- architectural review. [GOV §66314]
These standards aim to prevent negative impacts on the primary and nearby property.
However, a compliant ADU ordinance is limited by more specific rules set down by the state.
For example, an ADU — established as 1,200 square feet or smaller — cannot be larger than 50% of the primary dwelling’s existing floor area. It also cannot be sold or conveyed separately from the primary residence although exceptions exist. [GOV §66314(d)]
When HDC determines a local ordinance does not comply with legislation, notice is given and HCD then sets a deadline for the local agency to respond. The deadline after HDC’s notice of non-compliance is no longer than 30 days for the agency to either:
- amend the ordinance; or
- adopt the ordinance regardless and explain in the resolution adopting the ordinance why the ordinance is in compliance. [GOV §66326(b)(2)]
Should local agencies reject this straight-forward process by either ignoring the submission deadline or HCD’s feedback, they fully open the door for homeowners to ignore compliance with the ordinance as entirely void.
Related article:
