If you own a multifamily-zoned lot in Southern California and have been sitting on it because the entitlement process felt like a gamble, SB 684 changed the math.
Signed into law in October 2023 and operative as of July 1, 2024, this California lot split law gives qualifying landowners a ministerial — meaning by-right — path to subdivide a single lot into up to 10 parcels and build up to 10 residential units. No public hearings. No discretionary review. No environmental impact report. Just objective standards and a 60-day clock. Understanding this California lot split law is the first step to knowing whether your property qualifies.
Here’s exactly how it works.
What SB 684 Actually Does
Before this law, subdividing a parcel in California almost always meant navigating the discretionary review process — planning commission hearings, potential CEQA review, and months of uncertainty with no guaranteed outcome at the end. For smaller infill sites, that timeline and cost often made the project impossible to pencil.
SB 684 removes that uncertainty for qualifying sites. Under this California lot split law, a local agency must process your parcel map or tentative and final map ministerially — without discretionary review or a hearing. If they don’t approve or deny your completed application within 60 days, it is deemed approved automatically.
That is a fundamental shift in how small-scale subdivision works in California.
Does Your Property Qualify?
Not every lot qualifies. To use SB 684, your property must meet all of the following:
- Zoned for multifamily residential use
- No larger than 5 acres
- Located within an incorporated city that includes an urbanized area, or within an urbanized area in a county with a population over 600,000
- Substantially surrounded by qualified urban uses — meaning at least 75% of the parcel’s perimeter adjoins residential, commercial, retail, public institutional, or transit uses
- Not previously subdivided under SB 684
If you own property in Orange County, Los Angeles County, Riverside County, or San Bernardino County, the urbanized area and population thresholds are almost certainly met. The real variables are zoning and the surrounding use test — both of which your assessor records and a quick site review can confirm.
What You Can Build
Once your subdivision is approved, SB 684 allows up to 10 residential units across up to 10 new parcels. Each parcel must be at least 600 square feet, and the average net habitable floor area across all units cannot exceed 1,750 square feet. That cap is intentional — this law targets attainable housing, not large custom homes.
For the work we do at BuiltADU, that size profile is a natural match. HUD-approved manufactured homes — factory-built, installed on permanent foundations, registered as real property through Form 433A — deliver quality construction that fits comfortably within that footprint. You split the lot, place a manufactured home on each parcel as a standalone fee-simple residence, and evaluate ADU potential on qualifying parcels under separate law where the site and numbers support it.
Each unit becomes its own legal parcel with its own title. That means each one can be sold independently — a fundamentally different exit strategy than building a traditional apartment complex on a single lot and either holding it or selling the entire thing at once.
How the Approval Process Works
This is where the streamlined housing approval California landowners have been waiting for actually shows up in practice.
Once you submit a complete application, the local agency has 60 days to approve or deny it. If they deny it, they must return a full written explanation of what is deficient and how to remedy it — also within 60 days. If they take no action at all, the application is deemed approved.
The agency can apply objective zoning, subdivision, and design standards. What they cannot do is impose standards that physically prevent you from building to the densities the law allows, requirements that apply solely because you are using SB 684, or parking, setback, or floor area ratio requirements that would effectively kill the project.
There is also an important construction sequencing tool built into the law: you can apply for building permits on individual units before the final map records, provided you submit a recorded covenant tying the permit to the eventual map recording. That means work can start while the paperwork finalizes — a meaningful advantage for project timelines.
This streamlined housing approval process in California is one of the few entitlement tools that gives small operators real schedule certainty from day one.
What SB 684 Does Not Cover
A few hard limits worth knowing before you run numbers on a deal.
Parcels created under SB 684 are not eligible for further lot splits under SB 9. You get one subdivision pass per site under this law. Additionally, local agencies are not required to permit ADUs or JADUs on parcels created through SB 684. Some jurisdictions will allow them — and it is always worth confirming with your city or county — but ADU rights do not carry over automatically to the newly created parcels. Verify this before you build that assumption into your pro forma.
Finally, properties in single-family residential horsekeeping zones designated in specific master plans are exempt from this California lot split law, as long as the applicable jurisdiction has a compliant adopted housing element. If you are unsure whether your property falls into this category, confirm with a land use attorney before moving forward.
The Bottom Line for Southern California Landowners
SB 684 is one of the most practical development tools available right now for owners sitting on underutilized multifamily-zoned property. The streamlined housing approval California created under this bill — 60-day ministerial process, individual parcel sales, and alignment with manufactured home construction — makes this a real strategy, not a theoretical one.
If you own a qualifying lot in Southern California and want to understand what’s actually possible on your site, the analysis starts with three things: zoning, parcel size, and the surrounding use test. We run those numbers regularly. Reach out and we’ll walk through your specific property.
