Since 2017, California lawmakers have passed over 100 pieces of legislation intended to combat the growing housing affordability and availability crisis. National observers have focused particularly on laws that legalize building accessory dwelling units (ADUs) and duplexes in all residential areas, including neighborhoods previously reserved for single-family detached homes. But these are only one part of a multipronged approach: California has also passed laws that lower procedural hurdles for achieving the state’s long-standing housing production targets and add teeth to enforcing those targets.
Media attention charted the political battles in Sacramento to pass these laws—following the deal-making and compromises in committees and reporting the results of key votes through to Governor Gavin Newsom signing the bills into law. Like romantic comedies that end with weddings, such political narratives often imply that the successful passage of a law signals a happy ending. But in this case, it’s just the start of a new story—or rather, hundreds of new stories, with the scene of the action shifting back to cities and counties. Before property owners and developers can start building homes under the new rules, each local government across the state must revise their zoning and related land use regulations, which requires their own political and legislative negotiations. And given California’s long history of constraining development, especially in affluent communities, it is far from clear that implementation of the new state laws will go smoothly.
This piece puts California’s recent housing policy changes into a broader historical context, outlines the process by which localities implement state laws (or refuse to implement them), and previews how zoning reforms could be integrated with strategies to increase the supply of below-market housing.
California’s housing production has been a contentious and complicated issue for decades
The pro-housing movement has gained political momentum in recent years, but its modest legislative successes are pushing against decades of restrictive local zoning, underbuilding, and anti-growth policies backed by multiple influential constituencies.
California homeowners and local governments have a long history of asserting the right of local control over housing development, although the framing of their arguments has evolved. Since the early 20th century, cities and counties across the state have enforced local zoning codes that prohibit apartments on the majority of their land, claiming the need to protect property values and “neighborhood character.” In practice, by limiting new development to single-family detached homes, restrictive zoning makes it harder for young, low-income, and racially diverse households to move into affluent communities.
The 1970s saw the emergence of two political movements that substantially hindered California’s housing production, despite their good intentions. First was when organizations such as the Sierra Club mobilized suburban homeowners in support of greater environmental regulations on development, including the state’s signature California Environmental Quality Act (CEQA). While the original intent was to protect environmentally sensitive areas from development, CEQA is now frequently used to delay or block climate-friendly projects, including bike lanes and infill housing. The second movement was California’s taxpayer revolt, which resulted in Proposition 13, adopted in 1978 to cap property tax increases. Proposition 13 reduces turnover by discouraging long-term homeowners from selling their homes—significantly reducing the number of homes available to younger and newly arriving households. It also incentivizes local governments to restrict development of lower-cost housing and finance public services through impact fees, which are effectively a tax on new development.
The current debate is a continuation of long-standing tensions between older, more affluent homeowners and younger, more diverse renter households. Anti-growth homeowners—sometimes called “homevoters” or “NIMBYs” (short for “not in my backyard”)—are typically older, wealthier, and whiter than California’s overall population, and are disproportionately represented at community meetings and among elected officials. Pro-housing groups—or “YIMBYs,” short for “yes in my backyard”—represent a relatively new political movement pushing local and state officials to change zoning rules and allow an increased supply of diverse housing types. These groups, such as California YIMBY and Circulate San Diego, have helped pass policy changes at both the state and local level, discussed in more detail below.
State laws typically start with a broad policy framework and leave the details up to localities
Since 2016, California has adopted several new state-level policies designed to increase the supply of “missing middle” housing such as ADUs, duplexes, and lot splits. These laws are intended to create new opportunities for small-scale multifamily housing in low-density neighborhoods that were previously reserved exclusively for single-family detached homes. While the state laws set broad standards for ADUs, duplexes, and lot splits, local governments have some discretion in how to implement these laws in their local zoning and building codes.
As the experience with ADU legalization demonstrates, the details of policy design matter quite a lot for what gets built. Even after a 2016 state law prohibited California localities from banning ADUs outright, many local governments added “poison pills” to their design and procedural requirements that made ADUs physically or financially infeasible to build. Some local rules required property owners to create multiple off-street parking spaces for an ADU, or enforced wide setbacks from the parcel edges—both of which make it more difficult to add ADUs on smaller lots. Some communities only allowed ADUs to be occupied by relatives of the primary home’s occupant—effectively prohibiting the use of ADUs as income-generating rental properties.
Between 2019 and 2022, California’s legislature passed several additional laws closing off these loopholes and removing burdensome requirements. Only once a standard set of rules emerged across all communities did ADU production take off in earnest. Localities still have some discretion around ADU policies within this framework, such as the ability to increase the maximum unit size or offer pre-approved standard plans that allow applicants to skip the permitting process.
State policies legalizing duplexes and lot splits are newer than ADU policies, so the framework is still fairly general and may need revising if localities design additional poison pills to inhibit their development. For example, a 2021 state law, SB 9, allows homeowners to add a second unit to their lot in areas zoned for single-family use. But localities have considerable discretion over dimensional requirements, income standards for tenants, and design elements, which may hinder the policy’s goals.
In addition to legalizing particular structure types, California’s legislature and executive agencies have strengthened the state’s long-standing system aimed at boosting overall housing production. The Regional Housing Needs Allocation (RHNA) system assigns each locality quantitative targets for the number of homes to add over an eight-year period, and requires them to develop a “Housing Element” that describes how they will achieve their target. This framework has existed since 1969, but with limited enforcement; localities faced no real penalties for falling short. Recent policy changes have increased the target numbers for most communities, set specific affordability guidelines in addition to overall numbers, and greatly strengthened tools for enforcement. The legislature has also modestly revised the CEQA to exempt certain new structure types from its burdensome review process. Collectively, this set of statewide housing policy changes is intended to hold localities accountable for good faith efforts to produce more—and more diverse—housing.
Local legislative processes pose challenges for enacting state-mandated zoning reforms
Just as state laws are adopted through a structured process—hearings and votes in committees, then in the full legislature, then the executive’s signature—local governments adopt zoning changes through their own process. And in complying with new state mandates, that process can be slow and contentious in localities where elected officials or residents are hostile to the state’s goals. Even localities that broadly support the goals may be hampered by small groups of vocal opponents or limited staff resources and capacity.
The process to adopt or revise local laws (including zoning) in California generally follows a series of steps prescribed under state law, although it can vary slightly by city charter. The initial policy design phase—deciding details on how to incorporate state guidelines, described in the previous section—typically involves consultation between staff in the local planning department and elected officials (city councilors or county supervisors). To codify the policy changes into law, the local governmental body drafts an ordinance that revises existing regulations. The proposed ordinance is then introduced through a “reading” that gives local officials the chance to consider the recommended changes. Next, a public hearing must be held to allow comments on the proposed zoning changes; this gives residents the opportunity to voice their support or opposition. Based on public comments, elected officials may decide to revise the policy and return to the design phase. The revised zoning typically requires a majority vote from the legislative body to go into effect. Another potential chokepoint resides with mayors: If a mayor vetoes the revised zoning ordinance, the city council requires a two-thirds majority to override.
The state government has the final say on whether revisions to local zoning effectively comply with state guidelines. Because of the contentious nature of housing laws, the state has created two offices to oversee implementation: the California Housing Strike Force (within the California Department of Justice) and the Housing Accountability Unit (within the Department of Housing and Community Development). Last year, the Housing Strike Force, in collaboration with the California Attorney General, brought the city of Pasadena into compliance with SB 9 after the city exempted certain neighborhoods from following the law.
Multiple parties have filed lawsuits over the new state laws. For instance, six Los Angeles County communities filed lawsuits against the state, claiming that SB 9 is unconstitutional. The state can also sue localities, as exemplified in Huntington Beach, where the city council has stopped reviewing resident applications for ADUs, duplexes, and lot splits. Because SB 9 is quite new, evidence on the typical outcomes and timelines of these lawsuits is not yet available.
Implementation timelines will vary across jurisdictions due to their internal legislative processes, community engagement, and legal challenges. Additionally, localities with limited financial resources and staff capacity may need to hire consultants or seek technical assistance in order to revise their zoning—already a common practice in developing the Housing Elements required under the RHNA. The volume of new state policies—over 100 laws in six years—creates challenges even for high-capacity communities to keep up. Similar statewide zoning reforms in Massachusetts and Oregon suggest that it may take two to three years for zoning changes to be implemented by all localities, especially in hostile places.
Incorporating the new laws into localities’ broader housing affordability strategies
While many localities will have to be dragged kicking and screaming into complying with the bare minimum of the new state guidelines, some localities may take advantage of the new policy tools—and political cover provided by state oversight—to actively promote the development of lower-cost housing.
Two types of motivations may nudge localities toward more proactive steps in the next few years. First, elected officials perceive that residents hold them accountable for worsening housing affordability, creating political pressure to act. For example, Los Angeles Mayor Karen Bass highlighted voters’ concerns over homelessness and housing costs as a top issue in her first State of the City address.
Second, the enhanced housing production targets and stepped-up enforcement of the RHNA may encourage some localities to include ADUs and duplexes in their toolkit to expand low-income housing. The RHNA sets targets not just for overall housing production, but for specific tiers of affordability based on the percentage of area median income. In the process of revising their zoning to comply with the state guidelines, forward-thinking localities may choose to incorporate newly legal structure types to help meet their targets for low- and moderate-income homes. For instance, localities might consider setting aside vouchers to pair with newly built ADUs or partnering with local affordable housing providers to help homeowners through the permitting process.
Monitoring local implementation of statewide housing policies can identify promising models
State and local policymakers across the U.S. are watching California to learn how the recent flurry of statewide policies will play out in coming years. Will localities graciously accept the new mandates and bring their zoning regulations into compliance, or will they find more creative political and legal mechanisms to stymie the state’s goals, much like the earlier ADU experience? Can tools such as ADUs, duplexes, and lot splits be targeted to meet the needs of low- and moderate-income households? Will the package of housing reforms noticeably boost overall production and stabilize housing costs?
While it may take years for the aggregate effects to become apparent, monitoring localities’ actions and public statements can provide useful insights into short- and medium-term milestones. In particular, understanding the internal political discussions, policy design choices, and approach to community engagement—and how varied these approaches are across localities—can be helpful for state policymakers to see how their goals are being carried out.