California

California has the strongest statewide HOA-preemption regime in the US for accessory dwelling units, built from two bills: AB 670 (2019) voided ADU-prohibiting covenants on single-family residential lots, and AB 3182 (2020) extended and codified the preemption into the Davis-Stirling Common Interest Development Act (Civil Code §§ 4740 / 4741). The combination prohibits common-interest communities from banning ADUs, restricting rentals below 25% of separate interests, or treating ADUs as separate HOA interests. Limits remain: HOAs retain authority over reasonable design standards and statutory height limits, and the 2026 Carlsbad case (CalMatters coverage) established that an HOA's documented design-standards regime can effectively delay or constrain ADU approval short of outright prohibition.

California's flagship state-level ADU financing program — the CalHFA ADU Grant Program — is paused and has not been refunded since the original $100 million allocation was fully deployed 2023-12-28. The program provided up to $40,000 per qualifying homeowner for pre-construction and non-recurring closing costs and financed approximately 2,500 ADUs in two rounds. As of 2026-04, no new funding round has been announced in the state budget. CalHFA continues to publish anti-scam warnings because bad actors actively solicit homeowners claiming access to grant funds that no longer exist. State-level financing activity has shifted to local pilot programs (San Francisco, San Jose, Los Angeles, San Diego) and private financing products (Fannie Mae ADU mortgage, HELOC, construction-to-permanent).

• CalHFA ADU Grant Program
• HCD ADU Funding index

California's property insurance market has been in a structural crisis since 2023, exacerbated by the January 2025 Los Angeles wildfires. The California FAIR Plan — the state-chartered insurer of last resort — has absorbed the bulk of the admitted-market withdrawal and is itself under stress. Governor Newsom signed a package of stabilization bills in October 2025 (notably AB 1, the Insurance and Wildfire Safety Act, and AB 226, the FAIR Plan Stability Act). The FAIR Plan requested a 36% rate increase for spring 2026 to remain solvent. Commissioner Lara approved a temporary FAIR Plan expansion to include HOAs, farms, and affordable-housing developments with a $100M-per-location aggregate limit through 2028. None of the stabilization legislation is ADU-specific — ADUs follow the primary dwelling's coverage regime, with FAIR Plan as the fallback in wildfire-exposed ZIPs where the admitted market has withdrawn.

California's state-level ADU programs are concentrated at HCD (technical guidance, ordinance review, enforcement) and the paused CalHFA grant pipeline (covered under stateFinancing). The state does not operate a central pre-approved ADU plan library — instead, AB 1332 (2024) created a preemption framework for local pre-approved plans with a 30-day ministerial-approval deadline, and major cities (Los Angeles, San Diego, San Jose, Sacramento, Berkeley) have rolled out their own plan catalogs. The California YIMBY coalition and other housing-policy organizations play an influential role in bill drafting; they are not state agencies but effectively drive much of the ADU legislative agenda. The Title 24 code cycle (now 2025, in effect for 2026 permits) is the authoritative building-code baseline.

• California HCD Housing Policy Development division
• AB 1332 pre-approved plans framework
• California YIMBY — legislative coalition