California Housing Legislation Tracker
California has passed a wave of housing legislation since 2022 that directly affects construction financing. SB 9 created lot-split rights but a financing gap. AB 1033 allows ADU condominiumization. SB 543 introduced 'deemed approved' ADU permits. SB 1164 created a 15-year property tax exclusion for ADUs completed by 2030. This guide tracks every law affecting your construction financing options.
California has passed a wave of housing legislation since 2022 that directly affects construction financing — from SB 9 lot splits to ADU condominiumization to solar mandates. Understanding which laws create new building rights and which create new financing challenges is critical for homeowners planning construction projects. SB 9 (HOME Act, 2022) allows lot splits and duplexes on single-family parcels statewide but created a financing gap because most lenders have no products for newly created vacant lots. AB 1033 (2024) allows ADUs to be sold as condominiums in participating cities, creating a new exit strategy for ADU investors. The October 2025 legislative package (SB 543, AB 462, AB 1154, AB 1061) strengthened ADU/SB 9 enforcement with 'deemed approved' mechanisms, expanded ADU rights in coastal zones and historic districts, and narrowed JADU owner-occupancy requirements. Title 24 2022 solar mandates added $8,000-$15,000 to new construction costs statewide. SB 1164 created a 15-year property tax exclusion for ADUs completed by 2030, significantly improving ADU investment math. For construction loan borrowers, these laws affect what you can build, what lenders will finance, and how your project's economics work.
Key Facts
- SB 9 (2022) allows lot splits and duplexes on single-family parcels statewide but created a financing gap — most lenders have no products for newly created vacant lots.
- AB 1033 (2024) allows ADUs to be sold as condominiums in participating cities (San Jose, San Diego as of 2026), creating a new exit strategy for ADU investors.
- SB 543 (2026) introduces a 'deemed approved' mechanism — if a city fails to act on a complete ADU permit within 60 days, the permit is automatically approved.
- SB 1164 creates a 15-year property tax exclusion for ADUs completed by January 1, 2030 — saving approximately $37,500 on a $200,000 ADU.
- Title 24 solar mandates add $8,000-$15,000 to new residential construction costs statewide. Must be included in construction loan sizing.
- Fannie Mae SEL-2025-08 (October 2025) allows projected ADU rental income for qualification across all conventional products, not just HomeReady, capped at 30% of qualifying income.
- Five charter cities obtained a trial court exemption from SB 9 in April 2024. The appeal outcome (affecting up to 121 charter cities) remains unresolved as of April 2026.
Decision Rules
If: You are planning an SB 9 lot split
Then: Expect financing challenges — conventional lenders cannot underwrite newly created vacant lots. Plan for portfolio lenders, hard money, or home equity financing. Your existing mortgage lender must consent to the lot split or you must refinance first.
If: You are building an ADU and want to use projected rental income to qualify
Then: Fannie Mae SEL-2025-08 now allows this across all conventional products. Verify your lender has implemented the October 2025 update. Income is capped at 30% of qualifying income using 75% of market rent.
If: You are building new residential construction in California
Then: Title 24 solar compliance is mandatory. Budget $8,000-$15,000 for solar PV and include it in your construction loan amount from day one.
If: You are building an ADU and plan to complete it before 2030
Then: SB 1164 provides a 15-year property tax exclusion. Factor this into your investment math — it significantly improves the ROI of ADU construction.
If: Your ADU permit is taking longer than 60 days and was submitted after January 1, 2026
Then: Under SB 543, the permit should be deemed approved. Contact HCD if your city is not complying.
California-Specific
- All legislation in this topic is California-specific. These laws do not apply in other states.
- Local implementation varies significantly — some cities have been aggressive in implementing SB 9 and ADU law while others have resisted (resulting in enforcement actions by HCD and AG).
- The 2025-2026 legislative package represents the strongest enforcement teeth for housing law in California history — the 'deemed approved' mechanism and HCD review requirements remove most local agency discretion for ADU permits.
- County-level impacts vary: SB 9 lot splits are more financially viable in high-value coastal counties where the newly created lot has significant inherent value, even without a structure.
Common Misconceptions
SB 9 means I can build a fourplex on any single-family lot
SB 9 allows up to 2 primary units per lot (or 4 units if you split the lot into two parcels). But the law has significant exclusions: properties in Very High Fire Hazard Severity Zones, earthquake fault zones, flood hazard areas, and certain charter cities may be exempt. The theoretical maximum of 4 primary units requires a lot split, which triggers additional financing and mortgage consent requirements.
ADU permitting is now instant because of the 60-day deemed-approved rule
SB 543's deemed-approved mechanism only applies after a complete application is submitted. Cities still have a 15-business-day completeness review period before the 60-day clock starts. If the application is incomplete, the city can return it for corrections, resetting the timeline.
AB 1033 lets me sell my ADU anywhere in California
AB 1033 requires local opt-in. As of 2026, only San Jose and San Diego have adopted ordinances allowing ADU condominiumization. Check whether your city participates before factoring a sale into your financial plan.
These laws only matter for big developers
SB 9, ADU law, and AB 1033 were specifically designed for individual homeowners on single-family lots. They create building rights and financing strategies that apply to owner-occupied properties.
Limitations & Gaps
- Legislative landscape changes annually — specific bills and effective dates should be verified against current law.
- Charter city SB 9 litigation remains unresolved — outcome could affect 121 California charter cities.
- Local implementation varies significantly — check your specific city's ordinances and HCD compliance status.
- Financing products for SB 9 lot splits remain limited. As more transactions occur and comparable sales accumulate, conventional lending may become available.
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