SB 684 (Caballero, 2023) created a ministerial path to subdivide a multifamily-zoned lot of under five acres into up to ten fee-simple parcels and build a home on each. SB 1123 (2024) extended that path to vacant single-family lots starting July 1, 2025. Together they are the state's answer to the missing middle: townhome-scale projects that sell as individual homes.
SB 684 and SB 1123 analysis is not yet in the app, which models ADUs today. It is on the roadmap behind SB 9.
Core rules
- Up to 10 units on a lot of less than 5 acres; new parcels must be at least 600 square feet.
- The lot must be zoned multifamily (SB 684) or be a vacant single-family lot (SB 1123). "Vacant" means no existing dwelling.
- Ministerial approval of both the parcel map and the building permits, within 60 days of a complete application; no CEQA.
- Objective standards only; no requirement for parking near transit; setbacks follow the zone but cannot prevent the units.
- No demolition of protected or recently occupied housing.
Why fee simple matters
Unlike ADUs, which stay attached to the main parcel (unless the city allows AB 1033 condos), SB 684 homes sit on their own lots. Buyers finance them with ordinary conventional mortgages, no HOA is required, and the exit for the developer is a sale per home rather than a refinance. In a $900,000 townhome market, eight 1,400 square foot homes on a 12,000 square foot R3 lot is a very different project from eight ADUs.
SB 684 versus SB 1211
On the same multifamily lot, SB 1211 says keep the building and add up to eight rental ADUs; SB 684 says redevelop (where no protected housing is lost) and sell up to ten homes. The right answer depends on the existing building's income, tenant protections, and the gap between rental cap rates and for-sale prices. We model both in a consult.
Send us the parcel and we will tell you which pathway the lot wants.
Frequently asked questions
What is the minimum lot size under SB 684?
New parcels must be at least 600 square feet. The original lot must be under five acres.
Does SB 1123 apply to lots with an existing house?
No. SB 1123 applies to vacant single-family lots only. Lots with a home may use SB 9 or ADUs instead.
Informational only. Not legal, architectural, or investment advice. Confirm current rules with your local planning department.