Santa Barbara County lot split guide: SB 9, SB 684 & SB 1123 explained — how to split property into up to 10 parcels, and what the Coastal Zone changes.
Two very different state laws now let property owners subdivide a single lot — one allows two lots, the other allows up to ten. Here's how each one actually works, and where the Coastal Zone changes the math.
Last updated July 4, 2026
For years, "lot split" in California meant one thing: SB 9, and its cap of two new lots. That's no longer the whole story. Two additional state laws — SB 684 and SB 1123, collectively known as the Starter Home Revitalization Act — now allow qualifying lots to be subdivided into up to 10 parcels, with a streamlined, hearing-free approval process similar in spirit to SB 9 but considerably larger in scale. A third law, AB 130, tightens the clock local agencies have to review all of these applications.
If you own property in Santa Barbara, Montecito, or the Santa Ynez Valley and you've heard rumors of "splitting into ten lots," this is almost certainly what people are referring to. This guide walks through all three laws side by side, what each requires, and — critically — how the California Coastal Zone changes the picture for much of the Central Coast.
Bottom line up front: Which law applies to your property depends entirely on zoning and whether the lot is vacant. SB 9 works on any single-family lot and tops out at two lots and four units. SB 684 works on multifamily-zoned lots up to 5 acres and allows up to 10 parcels and 10 units. SB 1123 extends that same 10-parcel framework to vacant single-family-zoned lots up to 1.5 acres. A property can use one of these laws — never more than one on the same site.
The Two Paths to More Lots
Think of it as two separate doors into subdivision, each with a different key:
Door One — SB 9 (Urban Lot Split): Any qualifying single-family lot, split into two, up to two units per resulting lot. This is the law most homeowners have heard about since 2022.
Door Two — SB 684 / SB 1123 (Starter Home Revitalization Act): Qualifying multifamily-zoned lots (SB 684) or vacant single-family-zoned lots (SB 1123), split into as many as 10 parcels, with up to 10 homes total.
A parcel already split under one of these laws cannot also be split under the other — and a lot generally can't be run through the same process twice. The right door depends on your zoning, your lot size, and whether there's an existing home on the property.
SB 9: The Two-Lot Baseline
SB 9 remains the most widely used option because it applies to ordinary single-family lots with an existing home. In brief, it requires:
Single-family zoning, in an urbanized area
Each resulting lot at least 1,200 square feet, with neither lot smaller than 40% of the original parcel
Owner-occupancy of one unit for at least three years
No demolition of recently rented, rent-controlled, or deed-restricted housing
Exclusion of historic properties, wetlands, prime farmland, and other protected land
In the City of Santa Barbara's Coastal Zone, SB 9 splits are limited to specific zoning districts and can require a minimum lot size double the standard minimum. In unincorporated Santa Barbara County, including Montecito, SB 9 splits are exempt from the Growth Management Ordinance's cap on new construction, though Coastal Zone and Very High Fire Hazard Severity Zone restrictions still apply.
SB 684: Up to 10 Parcels on Multifamily-Zoned Land
SB 684, effective since mid-2024, created a ministerial, CEQA-exempt approval path for subdividing certain multifamily-zoned parcels into up to 10 lots, each supporting a small single-family "starter" home. Key requirements:
Zoning: The lot must be zoned for multifamily residential use.
Size: No larger than 5 acres, substantially surrounded by qualified urban uses.
Location: Within an incorporated city, or within an urbanized area in a county over 600,000 in population.
Parcel size: Each new parcel at least 600 square feet, unless the local agency allows smaller.
Home size cap: Average net habitable floor area across the project can't exceed 1,750 square feet — this law is built for modest, entry-level homes, not large custom builds.
Tenant protections: No displacement of rent-controlled, deed-restricted, or recently rented housing, and no use on a site with an Ellis Act withdrawal in the past 15 years.
Once an application is deemed complete, the local agency has 60 days to approve or deny it; no action within that window means automatic approval. No public hearing, no discretionary review, and no CEQA analysis — a dramatic change from the standard subdivision process under California's Subdivision Map Act.
SB 1123: Extending the 10-Parcel Framework to Vacant Single-Family Lots
SB 1123, effective July 1, 2025, extends the same streamlined 10-parcel, 10-unit framework to vacant lots zoned single-family — opening up a category of property SB 684 didn't reach. Its specific requirements:
Vacant lot only: No permanent habitable structure on the site (or an existing structure that's abandoned and uninhabitable), and not occupied by a renter within the past five years.
Size: Up to 1.5 acres, surrounded by substantially urban uses.
Parcel size: Each new parcel at least 1,200 square feet.
No minimum frontage: Local agencies cannot impose minimum parcel frontage requirements.
Density: If the site isn't identified in the local housing element, the project must reach at least 66% of the maximum density otherwise allowed.
No unit size cap: Unlike SB 684, SB 1123 does not impose the 1,750-square-foot average home size limit.
Local agencies may still apply objective height, design, and zoning standards, but cannot impose standards that would physically block the allowed density, and generally cannot require setbacks greater than four feet from the original lot line.
AB 130: Faster Clocks on All of the Above
AB 130, effective July 1, 2025, applies the state's Permit Streamlining Act to ministerial housing applications — including SB 9, SB 684, and SB 1123 projects. In practice, that means local agencies must determine whether an application is complete within 30 days of submission, and then approve or deny it within 60 days of that completeness determination. AB 130 also introduced the ability to designate a "remainder parcel" within an SB 684/1123 subdivision — a portion of the original lot that keeps its existing use and isn't counted toward the new unit total, which can be useful on sites with an existing structure the owner wants to keep in place.
Where the Coastal Zone Changes the Math — Again
As with SB 9, the California Coastal Zone is the single biggest variable for Santa Barbara-area properties considering SB 684 or SB 1123. Even where these laws otherwise eliminate hearings and discretionary review, projects located within the Coastal Zone are still generally subject to Coastal Development Permit requirements and public hearing procedures under the Coastal Act. Given how much of the Riviera, the Mesa, the Waterfront, Montecito's coastal-adjacent parcels, and the Gaviota Coast sit inside that boundary, this is a threshold question to answer before assuming a 10-parcel subdivision is realistic on a specific site.
Very High Fire Hazard Severity Zones — which cover much of the Santa Barbara foothills, parts of Montecito, and large portions of the Santa Ynez Valley — add a second layer of review under all three laws, generally requiring fire-hardened construction standards as a condition of ministerial approval.
SB 9 vs. SB 684 / SB 1123, Side by Side
Feature SB 9SB 684 / SB 1123 Max new lots210Max units4 (2 per lot)10Qualifying zoning Single-family Multifamily (SB 684) or vacant single-family (SB 1123) Max lot size No stated acreage cap5 acres (SB 684) / 1.5 acres (SB 1123)Min new parcel size1,200 sq ft600 sq ft (SB 684) / 1,200 sq ft (SB 1123)Home size limit None specified 1,750 sq ft average (SB 684 only) Owner-occupancy required Yes, 3 years No Coastal Zone treatment Additional local standards, doubled minimum lot size in some cities CDP and public hearing still required
What This Means If You're Thinking About Selling — or Buying
For owners of larger multifamily-zoned parcels or vacant single-family lots, SB 684 and SB 1123 represent a meaningfully bigger opportunity than SB 9 — the difference between adding one unit and building out a ten-home starter-home community. But the tighter home-size cap under SB 684, the vacancy requirement under SB 1123, and the Coastal Zone's hearing requirement mean eligibility has to be confirmed parcel by parcel before any of this gets marketed as a selling point.
For buyers, a property advertised as "10-parcel eligible" needs the same scrutiny as an SB 9 claim: confirm the zoning designation, confirm vacancy status if SB 1123 applies, check the Coastal Zone and fire hazard maps, and verify there's no prior subdivision history that would disqualify the site.
If you'd like, I can run a preliminary screen on a specific Central Coast parcel — zoning, Coastal Zone status, fire hazard designation, and which of these laws (if any) actually applies — as part of a broader conversation about the property's value.
Frequently Asked Questions
Can I really split my lot into 10 parcels in California?
In some cases, yes. SB 684 allows up to 10 parcels on qualifying multifamily-zoned lots up to 5 acres, and SB 1123 extends a similar process to vacant single-family-zoned lots up to 1.5 acres. Both require the resulting homes to average 1,750 square feet or less under SB 684, and each new parcel to meet minimum size requirements.
What is the difference between SB 9 and SB 684/SB 1123?
SB 9 allows a single-family lot to be split into two lots with up to two units each. SB 684 and SB 1123 allow a larger subdivision of up to 10 parcels and 10 units total, but only on multifamily-zoned lots (SB 684) or vacant single-family-zoned lots (SB 1123).
Does the Coastal Zone affect SB 684 and SB 1123 projects in Santa Barbara?
Yes. Unlike the hearing-free process these laws provide elsewhere, projects located within the California Coastal Zone still require a Coastal Development Permit and are generally subject to public hearing requirements under the Coastal Act.
What does AB 130 change about lot split timelines?
AB 130 applies the state Permit Streamlining Act to ministerial housing projects, including SB 9, SB 684, and SB 1123 applications. Local agencies must determine an application complete within 30 days and issue a decision within 60 days of that determination.
Can a property use both SB 9 and SB 684/1123?
No. A parcel that has been or will be subdivided under SB 684 or SB 1123 cannot also be split under SB 9, and vice versa. An owner has to choose the pathway that fits the property's zoning, vacancy status, and goals.
This article summarizes California Senate Bills 9, 684, and 1123, and Assembly Bill 130, along with locally adopted implementing ordinances, for general informational purposes. Zoning designations, coastal boundaries, fire hazard maps, and municipal codes change, and eligibility must be verified against your specific parcel with the applicable city or county planning department. This is not legal advice — consult a land use attorney or licensed surveyor for a definitive eligibility determination before making development or purchase decisions.
Wondering Which Law Applies to Your Property?
I can run a preliminary zoning, Coastal Zone, and fire hazard screen on your Central Coast property and talk through which subdivision pathway — if any — fits your goals.
Johannes Steenkamp, Realtor® SFR, SRES · Keller Williams Realty
CalDRE# 02057072
(805) 886-6581 · jsteenkamp@kw.com · www.johannessteenkamp.com
Serving Santa Barbara · Montecito · Santa Ynez Valley.