State Law | Small-Lot Subdivisions

SB 684, SB 1123 and AB 1751: Up to 10 Homes on Small Lots in California

SB 9 (2021) stops at two lots. SB 684 and SB 1123 go further: they let you divide qualifying land into as many as 10 small lots with 10 homes, through staff review with no public hearing. This page covers the rules in force through 2026, the rewrite that starts on January 1, 2027, and AB 1751, a new townhome law that starts the same day.

What the Law Is

SB 684 is Chapter 783, Statutes of 2023, approved by the Governor on October 11, 2023. Its title is: streamlined approval for "development projects of 10 or fewer residential units on urban lots under 5 acres." SB 1123 (Chapter 294, Statutes of 2024, approved September 19, 2024) added vacant single-family lots. The rules sit in two sections: Government Code 65852.28 for the homes and Government Code 66499.41 for the subdivision map.

The statute sets its own start dates. Section 65852.28 "shall become operative on July 1, 2024," and the SB 1123 amendments became operative July 1, 2025. The Legislative Counsel's digest of AB 1751 calls this law the "Starter Home Revitalization Act of 2021."

Which Land Qualifies Today

Through December 31, 2026, there are two kinds of eligible lot. The first is a lot zoned to allow multifamily homes, no larger than five acres. The second, added by SB 1123, is a vacant lot zoned for single-family homes, no larger than one and one-half acres. Both must be "substantially surrounded by qualified urban uses," a term of the statute for land with urban development around it.

Vacant has a strict meaning. The lot must have no permanent structure unless that structure is abandoned and uninhabitable. The project also cannot use housing that is rent-restricted or rent-controlled, or housing that tenants occupied in the five years before the application. A parcel where an owner used the Ellis Act to withdraw rental units in the past 15 years is out.

Location matters too. The lot must be in an incorporated city whose boundaries include part of a US Census urbanized area, or in an urbanized area or urban cluster in a county with more than 600,000 people. Public water and municipal sewer service are required.

The site exclusions are long: prime farmland or farmland of statewide importance, wetlands, very high fire hazard severity zones (and high or very high zones on the state's own maps), listed hazardous waste sites, earthquake fault zones unless built to the seismic code, the 100-year flood zone and regulatory floodway mapped by the Federal Emergency Management Agency (FEMA) with federal exceptions, land in a conservation plan, protected species habitat and conservation easements. The eligibility page compares these checks with SB 9 and accessory dwelling unit (ADU) law.

How Many Homes, and How Dense

The map may create 10 or fewer parcels, and the project may contain 10 or fewer homes. A remainder parcel that keeps its existing uses and gets no new homes does not count toward the 10. The homes may average no more than 1,750 net habitable square feet; garages, carports and unfinished attics and basements are left out.

There is also a minimum. If the site is not listed in the city's housing element (its state-required housing plan), the project must reach at least 66 percent of the maximum density the zone allows, or of the state default density, whichever is greater. The state defaults in Government Code 65583.2(c)(3)(B) are 30 units per acre in a metropolitan county, 20 in a suburban jurisdiction, 15 in an incorporated city in a nonmetropolitan county with a micropolitan area, and 10 in other unincorporated nonmetropolitan areas. In a metropolitan county, 66 percent of 30 is 19.8 units per acre. Cities cannot apply standards that physically block those densities.

What a City Cannot Require

Under Government Code 65852.28(b)(2), a city cannot impose setbacks between the new homes beyond what the building code requires, enclosed or covered parking, side and rear setbacks over four feet from the original lot line, or more parking than SB 9 allows, which is one space per home and none near qualifying transit. It cannot set a floor area ratio below 1.0 for three to seven homes, or below 1.25 for eight to ten. Floor area ratio is the total floor area of the buildings divided by the lot area, so 1.25 on a 10,000 square foot site means 12,500 square feet of building.

For the new parcels, the minimum size is 600 square feet, or 1,200 if zoned single-family, unless the city goes lower. No minimum width, depth or frontage applies beyond that. A homeowners association is not required unless the Davis-Stirling Act, the state law for shared-ownership developments, requires one.

The city must approve or deny a complete map application, and a complete housing application, within 60 days. If it does not, the application is deemed approved. A denial must list the defects in writing. A local inclusionary housing ordinance, which requires a share of affordable homes, still applies.

ADUs, SB 9 and Selling the Lots

A city does not have to allow ADUs or junior ADUs on parcels created through SB 684, and if it does, they do not count toward the 10. A parcel created under SB 684 cannot then use an SB 9 split, and a lot created by SB 9 or SB 684 cannot use SB 684.

Sales have a timing rule. Under 66499.41(e), "no person shall sell, lease, or finance" an SB 684 parcel separately until each parcel has a finished home, has an existing legal home, is common area, or is the last undeveloped parcel. A city can allow earlier sales by ordinance or as a map condition. Without that, a builder holds all the lots until the homes are done, so plan the construction loan around it.

The Altadena Exception

SB 1090 (Chapter 1006, Statutes of 2026), an urgency law in effect since September 30, 2026. It says SB 684 and SB 1123 do not apply to a project in ZIP Code 91001 or 91003 if the application is submitted on or after October 1, 2026. Earlier applications and 100 percent affordable projects by nonprofits are excepted. This version is repealed on January 1, 2030.

What SB 1116 Changes on January 1, 2027

SB 1116 (Chapter 808, Statutes of 2026) rewrites both code sections. Its digest says the changes apply to "applications received by local agencies on or after January 1, 2027." The new version must be "interpreted liberally in favor of producing the maximum number of total housing units," and it covers charter cities.

Sources: Gov. Code 65852.28, 66499.41 (versions operative January 1, 2027) and the SB 1116 digest.

One change decides which land qualifies. The five-acre limit and the "substantially surrounded" test give way to the site test in Public Resources Code 21080.66(a)(3), and the law will cover sites whose base zoning allows no more than 15 units, or 26,250 square feet of residential floor area. If you are deciding whether to file in late 2026 or in 2027, compare your site under both versions.

AB 1751 Townhomes, Starting 2027

AB 1751 (Chapter 781, Statutes of 2026), the "Missing Middle Townhome Ownership Act," was chaptered September 29, 2026 and takes effect January 1, 2027. It creates a staff-approval process, covering both the project and the subdivision map, for townhome projects of up to 150 homes. The law defines a townhome as a single-family home of three stories or less of occupiable space, sharing a wall or set at the minimum fire separation distance.

Projects must average 1,750 net habitable square feet per home, reach at least 75 percent of the state default density, and set aside at least 10 percent lower-income homes when they have 11 or more. Eligible land is zoned for multifamily homes, or is "underutilized" single-family land with no permanent residential building unless it is abandoned and uninhabitable. New parcels must be at least 600 square feet. Sites eligible for SB 79, parcels that had five or more homes in the past five years, lower-income housing element sites and the same hazard sites as SB 684 are excluded. The law "shall not apply to the City and County of San Francisco."

SB 9, SB 684 and AB 1751 Compared

Read the table by land type. On a lot in a single-family zone with a house you live in, SB 9 (2021) is the only one of the three that applies, and it stops at two lots. On a vacant single-family lot, SB 1123 allows up to 10 homes today, with a 1.5-acre limit. On multifamily-zoned land, SB 684 allows up to 10 small lots, and from 2027 AB 1751 adds an option for larger for-sale townhome projects of up to 150 homes, outside San Francisco.

Cities can write local rules on top. San Jose put its SB 684 rules into its municipal code in 2026, including a limit on ADUs and its own inclusionary rules; see the San Jose page. No statewide count of SB 684 projects was found in an official source.

Where to Go Next

Related on VanPlex: the missing middle guide and the California SB 9 comparison page.

Frequently Asked Questions

Official sources (checked October 2026)