For decades, building for-sale homes at a small scale in California was nearly impossible, not because the opportunity wasn't there, but because the approval process made it too slow, too uncertain, and too expensive. Senate Bill 684 (SB-684), signed into law in October 2023 and effective July 2024, changed that. For the first time, small developers can subdivide vacant or underused parcels in existing residential neighborhoods, and build up to ten for-sale homes, each on their own lot, through a fast, predictable process that bypasses the hearings and political delays that canceled projects before they ever broke ground. 

California's development approval process has long given local governments broad discretion to approve, delay, or cancel housing projects, whether this be through public hearings, planning commission votes, and lengthy environmental review. Senate Bill 684 strips that discretion away for qualifying projects by requiring ministerial approval, a checklist-based review where a local agency must approve a project if it meets the statutory criteria. Through ministerial approval, you avoid public hearings, political votes, and subjective judgments that have stalled or canceled projects in the past. If the boxes are checked, the permit must be issued. The law creates this pathway for up to ten homes on qualified multifamily infill sites: urban land that has long been overlooked due to outdated zoning and slow approvals.

Qualifying projects are also exempt from CEQA, the California Environmental Quality Act, the state's primary environmental review law. This law normally requires developers to study and disclose a project's potential environmental impacts, a process that can take years and be used by opponents to stall housing. Projects that take advantage of SB 684 can bypass CEQA entirely.

What makes SB 684 structurally significant is that it extended ministerial approval to subdivision maps for the first time in California. Before SB 684, several laws expedited building permits, but splitting a single lot into separate parcels required going through the traditional discretionary process. SB 684 closes that gap; now, a developer can subdivide and build through a single, no-hearing process, making for-sale housing finally feasible at a small scale.

California's housing shortage has been widely estimated at roughly 3.5 million homes. However, this crisis goes beyond numbers. Homeownership has always represented more than a place to live. It's stability, a sense of belonging, and a milestone that generations of Californians have worked toward. But that milestone has been slipping further out of reach. California's homeownership rate has been declining for years, and the state now has one of the lowest in the country.

To really understand the issue, we have to look more closely at the types of housing projects being built in the state. California has been building large single-family houses and large apartment complexes, which leaves an enormous gap in the middle. Modest, attainable for-sale homes on smaller lots, the kind that first-time buyers and working families can actually afford, have been nearly impossible to finance, permit, and construct under the old approval system. The risk and cost of discretionary review made small projects economically unviable.

SB-684 targets that gap directly. By unlocking small-scale for-sale housing, the law creates a new supply of entry-level homes for ownership in existing neighborhoods that are close to jobs, transit, and schools, without requiring the conversion of open land or the displacement of existing residents. It won't solve the housing crisis alone, but it opens a door that has been effectively closed.

Not every site zoned for multi-family residential use qualifies. The law is intended to incentivize infill development while maintaining existing protections against tenant displacement and against development on environmentally sensitive sites. SB-684's eligibility criteria are specific, and all of them must be met. Before submitting an application, a developer needs to be able to check every box.

• Zoning. The site must be zoned for multifamily residential use and be no larger than five acres. Single-family zoned lots don't qualify under SB-684, though SB-1123 (2024) extended similar provisions to vacant single-family lots. These lots must be 1.5 acres or less and have a minimum parcel size of 1,200 square feet.
• Urban Context. At least 75% of the property's boundary needs to border existing urban uses. Think homes, apartment buildings, shops, offices, or transit facilities. This ensures SB-684 is used for true development on overlooked urban lots, not the conversion of open or agricultural land. Sites that are bordered by farmland, open space, parks, undeveloped land, or federal property will likely not meet this requirement. 
• Location. The site must be located within an incorporated city or qualifying urbanized area. Rural and unincorporated land in smaller counties generally won't qualify.
• No Re-Splitting. The lot cannot have been previously created through SB-684 or an SB-9 lot split. The law cannot be used to repeatedly subdivide the same parcel.
• Environmental Constraints. Lots located in high fire hazard zones, wetlands, protected habitat, or land under conservation easements are all disqualified. Flood plains, earthquake fault zones, and hazardous waste sites require additional review and documentation to qualify. 
• Anti-Displacement. Projects cannot involve the demolition or alteration of rent-controlled units, deed-restricted affordable housing, or any housing that has been tenant-occupied within the last five years. Sites where an owner previously used the Ellis Act, a state law that allows landlords to permanently remove all units from the rental market, are also disqualified if that withdrawal happened within the past fifteen years.

Picture a vacant half-acre lot in an existing neighborhood surrounded by apartments, a corner store, and a bus stop. Before SB-684, that lot might have sat undeveloped for years, too small for a large apartment complex and too complicated for a small developer to navigate the approval process. Under SB-684, that same lot could become eight modest starter homes, each on its own parcel, each sold individually to a first-time buyer. 

SB-684 is designed to produce small, attainable for-sale homes on urban land that would otherwise go underdeveloped. The law sets clear boundaries on what can be built:

• Parcels. A lot can be subdivided into up to 10 new parcels.
• Units. The development may contain no more than 10 residential units in total.
• Parcel Size. Newly created parcels must be at least 600 square feet.
• Unit Size. The average unit size across the project cannot exceed 1,750 net habitable square feet. Keeping these homes modest and attainable by design.
• Density. Projects must build at the density the site calls for. If the site is listed in the city's housing plan, the development must include at least as many homes as the city projected. For all other sites, the project must be built to the maximum number of units allowed by zoning.

Note: AB 130 (2025) added one important provision: if there is already a structure on the property, like an existing home, the developer can set that portion aside as a remainder parcel. It stays untouched while the rest of the lot is developed and doesn't count against the ten-parcel limit. This opens up a much wider range of properties that previously wouldn't have qualified simply because something was already built on them.

In terms of ownership, SB-684 supports fee-simple lots, condominiums, housing cooperatives, and community land trusts. For most SB–684-qualified projects, fee simple can be the primary draw: each buyer owns their land outright, financing is conventional, and homes can be sold individually. 

With SB-684, cities are not obligated to permit accessory dwelling units (ADUs) or junior accessory dwelling units (JADUs) on parcels created under the law.

Before SB-684, even a small housing project could spend years in the approval pipeline waiting for hearing dates, navigating planning commission feedback, and hoping a city council vote went the right way. That uncertainty alone could be enough to kill most small projects before they start. 

SB-684 replaces that uncertainty with a simple rule: if your project meets the criteria, it gets approved. No hearings, no commission votes, no subjective judgment. Once a completed application is submitted, the city has 60 days from the date it is received to approve or deny it. If the city doesn't act within that window, the application is automatically considered approved. If denied, the city must provide a written explanation of exactly what's missing and how to fix it, also within 60 days.

SB-684 also created an early-building-permit pathway. Once a tentative map is approved, a developer can apply for building permits and begin construction before the final subdivision map is officially recorded, shaving meaningful time off the overall development timeline.

SB-684 presents a handful of challenges that are worth considering alongside its opportunities.

• Qualifying sites can be rarer than they appear. The law's eligibility criteria are layered and cumulative. Fire hazard zones, floodplains, tenant history, and environmental constraints eliminate a significant share of otherwise-zoned multifamily land, particularly in coastal cities and fire-prone regions where demand is highest. Finding a site that clears every hurdle can be a challenge. 
• Tenant protection matters. SB-684 includes meaningful anti-displacement protections. Sites with recent tenant history, rent control, or Ellis Act withdrawals within the past fifteen years are not eligible. It is important to verify a site's tenant history early in the process before moving forward
• City readiness varies. SB-684 is self-executing; cities are bound by it whether or not they've updated their internal procedures. But in jurisdictions that haven't trained staff or updated application checklists, developers may encounter inconsistent interpretations and informal resistance. As more projects move through the pipeline, this will smooth out over time.
• Inclusionary housing obligations still apply. SB-684 does not exempt projects from local affordability requirements. If a site is designated in the city's housing plan to serve lower-income households, the project must deliver those affordable units with a recorded restriction of at least 45 years.

Despite these constraints, the benefits are significant. For the first time, small developers have a guaranteed, fast-track path to build for-sale homes on urban infill land without the risk of discretionary denial. The CEQA exemption alone removes years of potential delay. The early building permit pathway compresses the construction timeline. And the law's support for community land trusts and housing cooperatives opens the door to ownership models that have historically struggled to move through traditional approval processes.

SB-684 won't work everywhere, and it won't work for every developer. But for the right site and the right project, it removes barriers that have made small-scale for-sale housing increasingly more difficult to build in California.

SB-9 and SB-684 are often mentioned in the same breath, and for good reason, as both laws use ministerial approval to streamline housing development in California. But they target different problems, different sites, and different types of builders.

SB-9 is fundamentally a homeowner tool. It applies to single-family zoned lots and allows an owner to split their lot into two parcels and build up to four units total. The catch is that the owner must live on one of the resulting lots for at least three years. It's designed for the individual homeowner who wants to add a unit, split off a portion of their lot, or create a small duplex, not for a developer building from scratch. For a deeper dive, check out our full overview of SB-9. 

SB-684 operates at a different scale and targets a different audience. It applies to multifamily-zoned land, allows up to 10 parcels and 10 units, and has no owner-occupancy requirement. A developer can acquire a vacant urban site or one with an existing structure and build an entire small subdivision of for-sale homes through a single streamlined process. Where SB-9 unlocks individual backyards, SB-684 unlocks underused infill land for small-scale residential development.

Think of them as complementary tools rather than competing ones. SB-9 is for homeowners looking to maximize the value of the land they already own in neighborhoods zoned for single-family residential uses. SB-684 is for builders looking to develop small for-sale projects on infill sites in areas zoned for multi-family residential uses. California needs both.

Interested in understanding what may be possible on your site? Contact Type Five to evaluate your property, discuss your development goals, and explore how California’s infill housing laws could apply to your project.