MasonCalifornia Assembly Bill 253 was signed into law with a specific intent: give applicants a faster path when their local jurisdiction is falling behind on plan review. The law allows developers to hire a private plan reviewer if a jurisdiction misses the 30-day review deadline. The private reviewer completes the check, the applicant moves forward, and the jurisdiction does not become a bottleneck.
On paper, the logic is straightforward. In practice, the law has generated more questions than most pieces of building regulation produce in a decade.
What the law actually does
AB 253 does not remove the jurisdiction from the process. The local building official retains authority over the final permit. What the law changes is who can perform the review and under what conditions.
When a jurisdiction fails to complete an initial plan review within 30 days of a complete application, the applicant can choose to hire a third-party private plan reviewer. The private reviewer must be licensed, must apply the same code the jurisdiction would apply, and must submit their findings in a format the jurisdiction can act on.
The jurisdiction can accept, reject, or require corrections to the private review. The permit still comes from the local authority.
The intent behind the bill
The panels and committee hearings that preceded AB 253 were largely focused on one data point: California housing production is constrained, in part, by permit processing delays. The bill's proponents argued that giving applicants a private option when the public process stalls would reduce those delays without lowering standards.
The code still governs. The professional still signs the review. The building still has to be safe. The bill changes the who, not the what.
What building officials are asking
The open questions from building officials fall into several categories. The first is coordination. When a private reviewer submits a plan check and the jurisdiction disagrees with specific findings, who resolves the conflict? The law describes a process, but the specifics of that process at the local level are still being worked out in many jurisdictions.
The second is code versioning. California allows local amendments, and the code edition in effect can vary by jurisdiction. A private reviewer working across multiple jurisdictions needs to track not just the California Building Code but the adopted local amendments for each project. The risk of applying the wrong amendment is real.
The third is accountability. When a private reviewer misses a code violation and the error surfaces during construction or occupancy inspection, the liability question becomes complicated. The building official who did not perform the review is still the authority of record. The private reviewer has their own professional liability. The applicant is caught between them.
What this means for private providers
Private plan review firms are watching AB 253 closely because it expands their addressable market significantly. Any project in a jurisdiction that misses its 30-day deadline becomes a potential engagement. For firms that can demonstrate consistency, code coverage, and professional accountability, that is a meaningful opportunity.
It also comes with higher scrutiny. The building officials who are skeptical of AB 253 are looking for any evidence that private review produces lower-quality outcomes. Firms entering this market under the law need to demonstrate that their process is as rigorous as a well-run municipal plan check.
That means documented processes, clear code citations, and review outputs that a building official can evaluate without ambiguity. It means being able to explain every flag and every approval if challenged.
The professional responsibility dimension
AB 253 does not change what plan review is. It changes who is permitted to do it in specific circumstances. The professional obligation is the same: review the plans against the applicable code, flag the conflicts, and stand behind the output.
The tools that support that work are the ones that show their reasoning, cite their sources, and give the reviewer control over every output. Not because the law requires it, but because that is what professional plan review looks like.
You can see exactly how Mason handles citations and reviewer control on the product page.
The law is about accountability. So is the work.