California’s Building Code Appeals Process: A Quiet but Crucial Lever for Housing

California’s housing crisis has precipitated substantial zoning and land use reforms, as well as funding investments. However, one of the most technical and least-examined components of the housing delivery system—the building code and its interpretation—plays a significant role in shaping what gets built, how quickly, and at what cost. Building codes are designed to ensure the safety and sustainability of the built environment, but rely on a fragmented and decentralized network of local building officials to administer. Residential building codes are interpreted locally across California’s 540 jurisdictions. This introduces layers of inconsistency and unpredictability that can compromise project feasibility and potentially undermine the State’s housing goals.

The enactment of Assembly Bill (AB) 130 in June 2025 signals a new willingness to revisit how California develops and administers its building codes. AB 130 establishes a six-year pause on state and local changes to the residential building standards (as codified in the California Building Standards Code and Title 14 of the California Code of Regulations) with limited exceptions for emergencies, fire safety, accessibility, or alignment with approved general plans.^[1] For the broader code landscape—including the California Building Code (CBC) and the California Existing Building Code (CEBC)—it also ends the past practice wherein the State can add new requirements every 18 months, instead only allowing updates every three years. The law also introduces a provision allowing residential projects based on approved model designs to continue under the original code for up to 10 years or until completion, unless the design undergoes a significant change.

These reforms beg the question of what other building code requirements or processes may warrant revisiting as the State continues to look for ways to boost the supply of new housing. This commentary draws on a review of the literature and interviews with code experts and officials to identify challenges with existing code application processes that can lead to uneven interpretation across the state and impact the feasibility of housing development—with the most marked impacts for more complex housing typologies, such as higher-density mixed-use projects or adaptive reuse of commercial buildings. The analysis also spotlights other California code appeal and interpretation processes that appear to lead to better alignment with state goals and shares policy directions that warrant further exploration to better rationalize the existing system.

How the Current System Works

Currently, the State of California adopts its building codes on a three-year cycle, largely drawing from the International Code Council’s model codes and layering in state-specific amendments. In addition, every intervening 18 months, the State issues further, generally more limited, code amendments and updates. The California Building Standards Commission (BSC) manages this rulemaking process, in coordination with other state agencies and departments.^[2] In addition, local jurisdictions have broad latitude to adopt more restrictive standards and to interpret provisions in their own way—authority rooted in the state constitution that reflects the longstanding value placed on home rule in areas of land use and building safety. While local jurisdictions are generally expected to file local code amendments with the BSC, there is no proactive cross-check to identify whether local changes have been appropriately filed with the State.

Local authorities across California’s 540 jurisdictions struggle to keep abreast of changes to the code every 18 months—and in practice must be familiar with multiple generations of code at once, as buildings under development may take multiple years to construct but are only subject to the code regime in effect at the time of approval. To stay abreast of changes, building officials engage consultants, request support from California Building Officials, and occasionally reach out directly to state entities for informal guidance or to request the publication of clarifying informational bulletins.^[3] This regulatory structure is predicated on the idea that local building departments are well-staffed, highly trained, and consistent in their approach. Yet interviews with stakeholders suggest that capacity varies widely, and that informal workarounds—such as building officials phoning peers in neighboring cities for advice—are often the sole mechanism for achieving consistency in good-faith interpretations of the dynamic code environment. The result is a patchwork system in which even basic concepts such as “floor area” or “occupant load” can be interpreted differently depending on individual inspectors or which side of a city boundary a project sits.

These variations are not merely technical disputes; they can have serious implications for housing feasibility. For example, policymakers are increasingly interested in converting vacant commercial properties into housing, a goal backed by executive orders and local initiatives. Yet the definition of “substantial improvement”—the threshold that determines when a project must meet full new construction standards—varies dramatically from one jurisdiction to another. In some cities, removing portions of an existing foundation or exterior wall triggers requirements that make reuse economically infeasible. In others, the same project might proceed under less burdensome rules.

When local building officials err or impose prohibitively expensive interpretations of code, there are few good options for builders to seek redress. State law generally requires the cooperation of the local building official to submit a formal request for clarification to a state entity, a process rarely used in practice.^[4] And while existing law provides builders with the ability to challenge a local code determination through a local appeals board, few cities and counties have created such boards. Further, state law stipulates that local jurisdictions that have not bothered to create local appeals boards should simply have their governing bodies (city council or board of supervisors) act as an appeals board. This leads to a system where an appeal by a builder is most likely to be heard by a body without relevant technical expertise that is also employing the same city staff person whose code-related decision is being contested.

For developers and homeowners alike, these inconsistencies and inabilities to effectively contest costly local amendments or interpretations can translate into delays, mandated redesigns, and added costs that ripple through the system.

Existing Models Offer a Path Forward

Interestingly, other parts of the state’s building code framework have appeals and interpretation systems that appear not only to be used more often, but are also potentially more fair, transparent, and accessible.

The State Fire Code, for example, allows any individual to request an interpretation when a local decision seems problematic. The State Fire Marshal maintains a Code Interpretations Committee (CIC), which meets monthly to review submitted requests, research relevant code history and precedent, and develop a recommended interpretation. Once the CIC reaches a decision that is formally approved, it is then published on the Fire Marshal’s website. While this system has its flaws (for example, appeals can only be heard if they are filed via physically mailed documents), it has produced a body of publicly available guidance on which local fire districts rely.

The California Historic Building Code offers another. Any affected individual may submit an appeal to the State Historical Building Safety Board (SHBSB) for items affected by the code, although decisions must be deemed to have some level of “statewide significance” to be considered. The appeal is reviewed by the Code Development and Appeals Advisory Committee, and a formal interpretation is subsequently promulgated, including to the State’s Building Standards Commission. The SHBSB may charge reasonable fees (up to cost) for reviewing appeals or publishing decisions. It establishes a three-level appeals process, ranging from staff-level clarifications to full board hearings. This layered approach provides flexibility: many questions can be resolved quickly and inexpensively, while more complex disputes can receive a higher level of review.

Beyond California, the International Code Council (ICC), which sets the code frameworks that each state adopts, employs a process for clarification that is generally well regarded. Any individual can submit a request for interpretation. ICC staff review and opine on items that require relatively simple clarification or forward requests deemed to raise complex or precedent-setting questions to the ICC Interpretations Committee. For the escalated requests, the Committee reviews the request, deliberates in open meetings, and publishes their final decisions on the ICC website. While not legally binding in any jurisdiction, they represent the official position of the ICC on how the code should be applied until clarified by a subsequent code change or erratum.

Policy Directions Worth Exploring

The models, as well as interviews with a range of building industry stakeholders, highlight possible directions for further reform to the California codes that govern residential building.

One possibility is strengthening the current process for appealing local code determinations such that any affected party, including developers or builders acting on their own, can receive additional review. Large cities could continue to operate their own internal appeals boards, but applicants dissatisfied with those rulings—or operating in jurisdictions without functioning boards—would also have the option to seek review at the state level. A strengthened state-level review process could be managed by the BSC in coordination with other state code agencies. And it could leverage the existing ICC process by routing incoming queries not only to respective state entities but also to the ICC when appropriate. Such a state-level review process would need to be multi-level, so that simple questions could be resolved by staff memo, reserving substantive engagement and/or more extended hearings for complex and nuanced considerations, with results published and indexed online.

When requests meet a threshold of statewide significance, state agencies and departments could use determinations to create a transparent body of guidance available to all jurisdictions, reducing uncertainty for future projects. The process could also evolve to centralize all code interpretation requests, such that items of fire, energy, or historical standards are routed through the BSC rather than going directly to the respective state entity. Such a centralized review process could help to ensure that matters of State interpretation take into account broader state policy goals intended to support housing production. For example, some local fire departments require greater levels of ladder access around the perimeter of multifamily buildings to facilitate increased fire protection. However, this may significantly reduce the number of homes that can be built in a multifamily development; the State may be better positioned to weigh these competing trade-offs.

Such a process could also potentially better facilitate dissemination of Alternative Means and Methods Requests (AMMR). An AMMR is an alternative to a specific requirement in a building code that is submitted to a code official when a project cannot meet a code requirement due to a physical limitation or when the applicant wants to use a new material or design. The proposal must be at least equivalent to the code in terms of quality, strength, effectiveness, fire resistance, durability, and safety. However, AMMRs are only considered and approved within a given jurisdiction, and often disseminated privately, only accessible to the public via a public records request. A central portal, likely managed by the BSC, that consolidates bulletins and interpretations from the California Department of Housing and Community Development (HCD), the California Energy Commission, the Fire Marshal, and other code authorities could be helpful in amplifying the impact of the rulings.

Some stakeholders have also suggested that local code amendments be more explicitly included under the State’s Housing Element framework as a “constraint,” similar to how high impact fees, protracted permit review processes, or other onerous land use policies are currently treated. Every eight years the State establishes housing targets through its Regional Housing Needs Allocation (RHNA) process, and cities and counties must enact land use plans that facilitate the required growth. This work typically starts with a local assessment to ensure the availability of adequately zoned land to meet those targets. But it must also, under state law, include a review of “constraints” that make attainment challenging. The State typically requires that, if localities want to count sites with existing uses toward their goals, the sites must have a reasonable probability of development within the eight-year RHNA cycle. A linkage here–i.e., that the State’s acceptance of a local Housing Element could hinge on its removal or amelioration of locally enacted building code amendments that impose feasibility concerns for new housing supply—would underscore the housing impact of code decisions and provide accountability at the local level.

All of these reforms, if implemented, would require additional expenditures for added staffing and costs. While some costs (such as those to process a more robust state appeal and interpretation process) might fully be recouped through user fees, other costs would clearly be additive. This layers on top of an environment in which interviews affirmed that many local staff are already not equipped to evaluate novel construction methods or assess complex reuse projects. Providing technical assistance funding to local jurisdictions, while expanding the informal technical assistance BSC currently provides into a more formalized clearinghouse, could support local decision-making while building a culture of shared learning. Over time, it could also help minimize some of the natural variation that emerges between jurisdictions, which while generally benign, complicates the work of designers and builders operating in multiple jurisdictions.

Conclusion

Any discussion of reform must contend with California’s strong tradition of local control. Local building officials argue, not without reason, that they are best positioned to understand the conditions in their communities and to evaluate project-specific circumstances. Interviews reveal skepticism about “heavy-handed” state interventions, with some officials emphasizing that peer-to-peer consultation already functions as an informal check on interpretation. Clearly more research on this subject is needed, particularly to better understand best practices in states outside of California.

The current housing crisis, in which rising costs have served as a major brake on new supply, raises the stakes of inconsistency and inefficiency. Just as state policymakers have stepped in to standardize planning processes—through measures like Senate Bill 35, Accessory Dwelling Unit (ADU) laws, and density bonus reforms—there is a case to be made that code administration deserves similar attention. The challenge will be to design a system that respects local expertise while ensuring that decisions support, rather than undermine, statewide housing objectives. Further timely research on the issues raised in this commentary will be an important next step. Regardless, recognizing building code administration as a form of housing policy—and treating it with the same seriousness as other aspects of the system—would be a significant step toward addressing California’s housing crisis.

Acknowledgments

Thanks to Mike Malinowski, Mark Gangi, Crystal Sujeski, Eric Driever, Bob Raymer, Stoyan Bumbalov, Doug McCauley, Kyle Krause, and Bob Chase for their input and/or thoughtful reviews of prior drafts of this commentary. And thanks to Terner Center and Labs staff and faculty Michelle Boyd, Stephanie Hawke, Sheela Jivan, Sarah Karlinsky, and Carolina Reid for their reviews and Tyler Pullen, in particular, for his assistance in shaping the initial direction of the piece and serving as a helpful sounding board.

The views expressed in this piece do not represent the institutional views of UC Berkeley or the Terner Center’s funders. Funders do not determine research findings or recommendations in the Terner Center’s research and policy reports.

Endnotes

^[1] Exceptions under AB 130 are fairly narrowly constrained to wildfire mitigation efforts and emergency standards to protect health and safety, as well as modifications similar to those filed before the building freeze took effect or that are necessary to implement a local code amendment that aligns with a general plan approved on or before June 10, 2025 that permits mixed-fuel residential construction, incentivizes all-electric construction, or otherwise modifies various administrative practices.

^[2] Participating state entities include the California Department of Housing and Community Development (HCD) for residential and housing standards; the Office of the State Fire Marshal (CAL FIRE) for fire and life-safety; the Division of the State Architect (DSA) for state buildings and public schools (including accessibility); the Department of Health Care Access and Information (HCAI) for hospitals, clinics, and health facilities; and the California Energy Commission (CEC) for the Energy Code and related administrative provisions.

^[3] Local building officials, inspectors, and plan examiners are statutorily required (under Chapter 623, Statutes of 1995) to complete 45 hours of continuing education every three years. The statute is silent as to the content of such courses and does not make responsible any state agency for ensuring such training meets the broader goals and objectives of the state.

^[4] BSC staff report that such appeals have been filed perhaps once or twice in the past 15 years.