SB 9 Lot Split Financing in California
How to finance construction on SB 9 lot splits — the financing gap nobody covers.
California SB 9 (the HOME Act, effective January 1, 2022) allows homeowners on single-family zoned lots to pursue two distinct but combinable pathways: (1) build a duplex (two primary units) on their existing lot without a lot split, and (2) perform an Urban Lot Split creating two separate parcels, each eligible for up to two units. The theoretical maximum is 4 primary units on what was one single-family lot; when combined with ADU and JADU law, jurisdictions may allow up to 8–10 units in permissive cities. Financing is the single largest practical barrier. SB 9 does not create new loan products—it creates a legal entitlement that lenders have been slow to underwrite. Key obstacles include: existing mortgage lenders must consent to a lot split (or the mortgage must be refinanced or paid off first); newly created vacant lots from a split have no comparable sales and fail Fannie/Freddie conforming standards; and few lenders have built SB 9-specific programs. Homeowners typically finance SB 9 projects through home equity (HELOC, cash-out refi), construction loans from portfolio lenders or community banks, hard money/private lenders, or a combination. The owner-occupancy requirement (3-year affidavit for lot splits) limits investor use but does not prevent eventual sale of the second parcel after construction. A Governor's Executive Order (July 2025) suspended SB 9 in LA County wildfire burn areas, and a 2024 trial court ruling exempted five charter cities from SB 9 (currently on appeal). The 2025 legislative package (SB 543, AB 462, AB 1154, and a new SB 9 bill) strengthened ADU/SB 9 enforcement mechanisms effective January 1, 2026, and AB 1061 extended SB 9 to historic districts (no demolition). Total realistic cost for a complete SB 9 lot split + duplex build in California ranges from $400,000–$900,000+; timelines run 18–36 months. ROI is highly market-dependent.
Key Facts
- SB 9 took effect January 1, 2022, and requires ministerial (non-discretionary) approval of qualifying two-unit developments and urban lot splits on single-family zoned parcels statewide.
- The owner-occupancy affidavit for lot splits requires the applicant to sign a recorded statement of intent to occupy one unit on one of the resulting parcels as their primary residence for a minimum of 3 years from the date of lot split approval. Violation is perjury — a felony carrying up to 4 years in prison.
- The owner-occupancy requirement applies ONLY to the lot split pathway — NOT to the two-unit development pathway on an intact lot. Homeowners building a duplex without splitting the lot do NOT need lender consent or an owner-occupancy affidavit.
- On April 22, 2024, a Los Angeles County Superior Court ruled that SB 9 does not apply to California charter cities, finding it unconstitutional as applied because it was not reasonably related to its stated purpose (affordable housing) and not narrowly tailored. The ruling is binding only on the 5 petitioner cities (Redondo Beach, Carson, Torrance, Whittier, Del Mar). The California Attorney General filed a notice of appeal in June 2024.
- SB 543, AB 462, AB 1154, and a new SB 9 bill were signed by Governor Newsom on October 10, 2025, and took effect January 1, 2026 (AB 462 immediately as an urgency measure). These are the most significant ADU/SB 9 reforms since 2017.
- SB 543's 'deemed approved' mechanism: if a local agency fails to act on a complete ADU/SB 9 application within the 60-day review period, the permit is automatically deemed approved and the applicant can proceed with construction.
- AB 1061 (effective January 1, 2026) extended SB 9 to historic districts, allowing ministerial approval of lot splits and duplexes as long as no existing historic structure is demolished or altered. Previously, historic districts were categorically excluded.
- Governor Newsom's Executive Order N-32-25 (July 2025) allowed local governments in LA County to restrict or suspend SB 9 in wildfire burn areas including Pacific Palisades, Malibu, Altadena, and Sunset Mesa. YIMBY Law filed a lawsuit challenging this order in December 2025.
- Newly split SB 9 vacant lots cannot qualify for Fannie Mae, Freddie Mac, FHA, or VA conforming mortgages — these parcels lack prior sales comparables, have no structure, and fail seasoning requirements. Financing the new parcel typically requires portfolio lenders, hard money, or cash buyers.
- Each resulting lot from an SB 9 split must be at least 1,200 sq ft and no parcel can be less than 40% of the original (maximum 60/40 split). Original lot must be at least 2,400 sq ft to be eligible for a split.
- The Terner Center for Housing Innovation at UC Berkeley estimated that less than 2% of single-family lots in California are likely to be financially viable SB 9 projects under qualifying conditions, physical capacity, and financial feasibility constraints.
- As of October 2024, only 23 SB 9 applications had ever been submitted to the City of San Diego, with only 7 approved — illustrating that the law remains dramatically underutilized due to financing barriers, local resistance, and practical complexity.
- A lot split creates two new APNs (Assessor's Parcel Numbers), triggering property tax reassessment on the improvements built on each lot. The retained parcel may also see reassessment if the split changes its configuration materially. Consult a tax professional early.
- SB 9 units cannot be used for short-term rentals (less than 30 days). This prohibition applies to all units created under SB 9 provisions.
- HOA CC&Rs (Covenants, Conditions, and Restrictions) are private restrictions that SB 9 does NOT override. If a property's HOA prohibits lot splits or additional units, SB 9 does not grant the homeowner the right to proceed over the HOA's objection.
Decision Rules
If: Homeowner has an existing mortgage and wants to split the lot
Then: Lender consent via partial release is required BEFORE recording the lot split. If lender refuses or mortgage terms prohibit partial release, refinance with an SB 9-aware lender reflecting the new reduced lot size. If refinancing is not viable, consider paying off the mortgage (possibly via hard money). Do NOT proceed with lot split without lender consent — it triggers acceleration clause.
If: Homeowner wants to add a second unit WITHOUT splitting the lot
Then: No lender consent is needed for the two-unit (duplex) pathway. Owner-occupancy affidavit is not required. This is the simpler path. Finance via HELOC, cash-out refi, or construction loan on the existing property.
If: Homeowner is an investor with no intent to occupy either parcel
Then: SB 9 lot split pathway is not available — the owner-occupancy affidavit (3-year primary residence requirement) is mandatory for lot splits. The two-unit/duplex pathway on an intact lot may be available depending on local ordinance, but owner-occupancy is often not required for this pathway at the state level. Verify local ordinance. Community land trusts and qualified nonprofits are exempt from the affidavit requirement.
If: Property is in a charter city (California has approximately 121 charter cities)
Then: Verify current legal status before investing in SB 9. The April 2024 Redondo Beach ruling exempted 5 charter cities from SB 9; the AG has appealed. If the property is in one of the 5 petitioner cities (Redondo Beach, Carson, Torrance, Whittier, Del Mar), SB 9 currently does not apply. For other charter cities, the law still applies pending appellate decision. Check with a California land use attorney.
If: Property is in a wildfire burn area of LA County (Pacific Palisades, Malibu, Altadena, Sunset Mesa)
Then: Governor's Executive Order N-32-25 (July 2025) allows local governments to restrict SB 9 in these areas. Verify current local ordinance before proceeding. YIMBY Law lawsuit against the order was filed December 2025; outcome not confirmed. Exercise caution.
If: Property was occupied by a tenant within the last 3 years
Then: Property is ineligible for SB 9 under both the lot split and two-unit development pathways. SB 9 requires that no unit on the property has been tenant-occupied within 3 years of the application date.
If: Property has had an Ellis Act eviction within the last 15 years
Then: Property is ineligible for SB 9. This applies to both the lot split and two-unit development pathways.
If: Project includes both a lot split AND two primary units on each lot (full combination)
Then: Local agencies are NOT required to additionally permit ADUs under this full combination. Some cities may still allow ADUs as a matter of local policy. Do NOT assume the maximum 8-unit count without confirming local ordinance.
If: Project adds ADUs to the lot BEFORE performing the lot split
Then: This sequencing may preserve the right to have the pre-existing ADU on the retained parcel separately from the two-unit-per-lot limit on the new parcel. Conversely, existing ADUs may count against the per-lot unit limit after the split. Verify local interpretation before executing the sequence.
If: Homeowner is in a historic district
Then: As of January 1, 2026 (AB 1061), SB 9 projects in historic districts are permitted ministerially IF no historic structure is demolished or altered. This is a significant expansion. Consult with a historic preservation expert to confirm what qualifies as 'alteration' under local rules.
If: Homeowner needs construction financing for the new unit(s)
Then: Approach portfolio lenders, community banks, or credit unions with California construction experience first. Major conventional banks and Fannie/Freddie programs are unlikely to fit. If those are unavailable, use hard money as bridge and plan to refinance upon CO. Confirm lender's SB 9 familiarity upfront by asking directly whether they have done prior SB 9 construction loans.
If: Applicant submits a complete SB 9 application and the city does not act within 60 days
Then: As of January 1, 2026 (SB 543), the permit is automatically deemed approved. Applicant may proceed with construction under the submitted plans. Document all submission dates and application completeness determination carefully.
California-Specific
- SB 9 is a California-only state law — it does not apply in any other state
- California has approximately 121 charter cities that may have different SB 9 obligations pending the appeal of the Redondo Beach ruling
- California's ADU laws (AB 976 permanently eliminated owner-occupancy for ADUs; AB 1154 relaxed JADU owner-occupancy) interact with SB 9 to create complex multi-unit development scenarios
- California construction costs are among the highest in the country — $300–$500+/sq ft for new construction; high-cost coastal markets (Bay Area, coastal LA, San Diego) typically exceed $500/sq ft
- CalHFA ADU predevelopment grant program can offset early SB 9 costs for qualifying projects that include an ADU
- California Proposition 19 (2020) affects property tax reassessment rules when property changes ownership — relevant when selling an SB 9 lot to a non-family buyer
- California Coastal Act applies in coastal zones — SB 9 does not supersede Coastal Development Permit requirements; AB 462 (2026) streamlined CDP timelines for ADUs in coastal zones
- SB 9 does not override HOA CC&Rs — private deed restrictions remain enforceable
- California requires ministerial approval within 60 days of a complete application; SB 543 (2026) adds 'deemed approved' remedy for city inaction; completeness determination must occur within 15 business days of submittal
- SB 9's impact fees cannot be waived for new construction units — unlike ADUs under 750 sq ft which are exempt from development impact fees and school fees under SB 543
- Earthquake fault zones (Alquist-Priolo) are a significant exclusion in California given the prevalence of fault zones throughout the state, especially in the Bay Area and Southern California
- Very High Fire Hazard Severity Zone (VHFHSZ) exclusion is significant in California — large portions of hillside and foothill communities across the state are in VHFHSZ
Common Misconceptions
SB 9 allows any California homeowner to automatically split their lot and build 4 units
Less than 2% of California single-family lots are estimated to be viable SB 9 projects. Eligibility exclusions (tenant history, Ellis Act, fire zones, earthquake zones, flood zones, HOA restrictions, charter city exemptions, minimum lot size) eliminate a large share of properties. Financial feasibility is a separate constraint even for technically eligible lots.
SB 9 lot splits are easy to finance with a traditional mortgage
Newly created SB 9 lots are not eligible for Fannie Mae, Freddie Mac, FHA, or VA conforming loans. Financing requires portfolio lenders, hard money, or cash. No major bank has a publicized SB 9-specific product. This is the single biggest practical barrier to SB 9 adoption.
The owner-occupancy requirement applies to all SB 9 projects
The 3-year owner-occupancy affidavit applies ONLY to the urban lot split pathway. The two-unit development/duplex pathway on an intact lot does NOT require an owner-occupancy affidavit at the state level (though some cities may add this via local ordinance). Investors can use the duplex pathway on an intact lot in many jurisdictions.
SB 9 allows 8 or more units on any single-family lot
HCD's official position: SB 9 requires local agencies to allow a maximum of 4 primary units in the lot area previously used for one single-family home. When BOTH the lot split AND the two-unit provision are invoked, local agencies are NOT required to additionally permit ADUs. The 8-unit or 10-unit scenarios require local permissiveness beyond state mandates and are not universally available.
SB 9 overrides HOA rules
SB 9 is a public zoning law. It does not override private CC&Rs or HOA rules. Homeowners in HOA communities must obtain HOA approval (if required by their CC&Rs) in addition to city ministerial approval. If the HOA prohibits lot splits or additional units, SB 9 does not provide a remedy.
SB 9 projects in historic districts are still prohibited after 2026
AB 1061 (effective January 1, 2026) extended SB 9 to historic districts, allowing ministerial approval of lot splits and duplexes as long as no existing historic structure is demolished or altered. Previously, historic districts were excluded.
If a city denies an SB 9 application, the homeowner has no recourse
SB 9 requires ministerial approval — cities cannot deny a qualifying application based on discretionary judgment. If a complete application is denied without a lawful objective basis, the homeowner can: (1) challenge the denial with California HCD, (2) pursue legal action, or (3) after January 1, 2026, invoke SB 543's deemed-approved mechanism if the city failed to act within 60 days of a complete application.
You can split your lot at any time without telling your mortgage lender
Proceeding with a lot split without explicit mortgage lender consent violates the mortgage agreement and can trigger immediate full repayment of the loan (acceleration clause). Lender consent is mandatory — via partial release of mortgage or refinance.
SB 9 applies the same way in all California cities
While SB 9 is a statewide law, local ordinances govern many specifics (setbacks, design standards, parking). Charter cities have a pending legal exemption (Redondo Beach ruling, on appeal). Some cities have added procedural requirements. Los Angeles County wildfire areas have a Governor's executive order allowing local restrictions. Implementation genuinely varies.
Limitations & Gaps
- No confirmed named SB 9-specific loan products from any major California lender were identified in research — the financing landscape is fragmented and borrowers must identify portfolio lenders through brokers or referrals
- The appellate outcome of Attorney General Bonta's appeal of the Redondo Beach charter city ruling is not known as of April 2026 — this is a material legal uncertainty affecting up to 121 California charter cities
- The outcome of YIMBY Law's lawsuit against Governor Newsom's Executive Order suspending SB 9 in LA County wildfire areas is not confirmed as of April 2026
- CalHFA ADU predevelopment grant amounts and current program availability were inconsistently reported across sources ($25,000 vs. $40,000) — verify current program terms directly with CalHFA
- Specific lender interest rate terms and LTV ratios for SB 9 construction loans are not publicly available from named lenders — rates cited (10–12% for hard money) reflect market conditions as of early 2026 and are subject to change
- Cost and ROI estimates are market-derived ranges from practitioner sources, not verified transaction data — actual project economics depend heavily on market, lot configuration, soil conditions, contractor pricing, and permit timing
- SB 9 adoption data is sparse — the San Diego statistic (23 applications as of October 2024) is a data point but may not reflect statewide trends, and more recent statewide adoption data was not available in research
- The interaction between SB 9 and California Proposition 13 property tax rules (including Prop 19) for lot splits and new construction was not fully researched — recommend flagging for users to consult a property tax professional
- HOA CC&R analysis for specific communities is not possible at a general knowledge base level — every HOA community requires individual review
- The 2025 SB 9 (Arreguín) bill's specific enforcement mechanisms (null and void ordinances for noncompliant local agencies) are newly effective as of January 2026 — real-world enforcement track record is not yet established
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