SB-9 lets eligible single-family owners in Ventura County split one lot into two and place up to two units on each — potentially four homes where one stood. But strict eligibility rules, an owner-occupancy pledge, and city-by-city standards mean far fewer lots qualify than headlines suggest, as of 2026.
What SB-9 is and what it actually permits
Senate Bill 9, the California Housing Opportunity and More Efficiency (HOME) Act, took effect in January 2022. It created a ministerial — meaning no discretionary hearing — path to two things on qualifying single-family-zoned lots: an urban lot split into two parcels, and the development of up to two units per resulting parcel.
Combined, that is the much-quoted 'up to four units' outcome. In practice, the two-units-per-lot piece overlaps heavily with existing ADU law, and many Ventura County owners get a better result through standard ADU rules. SB-9's real power is the lot split, which lets you create a separately sellable parcel.
The eligibility limits most owners miss
SB-9 sounds expansive until you read the exclusions. A lot does not qualify if it is in a high or very-high fire-hazard severity zone without mitigation, a designated wetland, a historic district, prime farmland, or an earthquake fault zone — and large parts of unincorporated Ventura County and the hillside edges of cities fall into fire-hazard mapping.
There are also tenant protections: SB-9 cannot be used if it would require demolishing or altering housing that is rent-restricted, subject to rent control, or occupied by a tenant in the prior three years. And the law generally bars splitting a lot if the owner or an adjacent owner already used SB-9 on a neighboring parcel.
| Requirement | Typical SB-9 standard |
|---|---|
| Zoning | Single-family residential only |
| Lot split result | Two parcels, each >= 1,200 sq ft |
| New parcel balance | Neither under 40% of original |
| Owner occupancy | 3-year pledge after a lot split |
| Excluded land | Fire, flood, historic, farmland |
| Recent tenants | No tenant-occupied unit in 3 yrs |
The owner-occupancy pledge and the no-STR rule
If you do an SB-9 lot split, you must sign an affidavit promising to occupy one of the units as your principal residence for at least three years from the date of the split. That single requirement rules out most pure investors who wanted to split, build, and sell or rent everything immediately.
SB-9 units also generally cannot be used as short-term rentals — the law contemplates longer-term housing. Short-term rental rules are separately regulated by each city anyway, and those rules change, so verify current local ordinances before counting on any nightly-rental income.
How Ventura County cities apply SB-9 differently
SB-9 is state law, but cities adopt local objective standards — setbacks, height, design, and parking — within the limits the state allows. That is why two owners with similar lots in Simi Valley, Thousand Oaks, Camarillo, or unincorporated county land can get different outcomes.
As of 2026, cities cannot impose standards that would physically preclude two 800-square-foot units, and they cannot require more than one off-street parking space per unit (often zero near transit). But they can — and do — apply fire-access, grading, and tree-protection rules that make hillside Ventura County lots impractical to split. Always pull the specific city's SB-9 ordinance; they are revised regularly.
What I tell owners weighing an SB-9 split
Here is my honest take after walking clients through this: SB-9 is a niche tool, not a mass opportunity. It works best for an owner with a genuinely large, flat, non-hazard lot in a city with workable standards, who plans to live on site for at least three years and wants to create a parcel for family or future sale.
If you are a straightforward income investor, an ADU almost always gets you to rental income faster, with no occupancy pledge and fewer eligibility traps. Before spending money on survey and design work, get a parcel-specific feasibility opinion. I can help you screen whether your lot is even a candidate before you hire a civil engineer.
Frequently Asked Questions
Can I split my lot under SB-9 and sell both halves?
You can eventually sell, but a lot split triggers a three-year owner-occupancy pledge on one unit. You cannot split, build, and immediately sell everything as a pure investment play.
Does SB-9 override my HOA?
Not directly. SB-9 limits city discretion, but private HOA covenants can still restrict what you build. Check your CC&Rs alongside the city ordinance.
Is SB-9 better than building an ADU?
Usually not for income investors. ADU law has no occupancy pledge and fewer eligibility exclusions. SB-9's advantage is creating a separately deeded parcel — verify which fits your goals.
Are hillside Ventura County lots eligible for SB-9?
Often not. Many hillside parcels sit in high or very-high fire-hazard severity zones, which can disqualify a lot or require mitigation. Confirm fire-zone mapping for your address.
Have SB-9 rules changed since 2022?
California housing law is amended frequently, and cities update their local SB-9 standards regularly. Always verify the current state law and your city's ordinance before acting.
