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SB-9 Lot Split

Navigating the SB-9 lot split process can be complex, often requiring coordination with planning departments, engineers, and surveyors.

We are an LA-based land use consulting firm specializing in entitlements and permitting, helping property owners across Southern California move projects from concept through approval.

For homeowners considering an SB-9 lot split, we provide guidance to help determine the best path forward and move projects efficiently through review.

Why SB-9 Was Created

SB-9 was enacted as part of California’s broader response to the ongoing housing crisis, which has created a critical need for increased housing supply, particularly within single-family zones where development has historically been limited.

Under California Government Code, SB-9 allows qualifying homeowners to create additional housing opportunities by subdividing residential parcels and increasing density on eligible lots. The goal is to enable more housing in existing neighborhoods without requiring large-scale rezoning or discretionary approvals.

The law supports affordable housing production by unlocking underutilized land in established residential areas. By allowing lot splits and additional units on a single-family parcel, SB-9 creates more housing options while maintaining local zoning frameworks and reducing the need for infrastructure expansion.

What Is an SB-9 Lot Split?

An SB-9 lot split allows qualified homeowners to divide a single parcel of land into two separate lots. It comes from the SB-9, a state law that aims to create new housing opportunities on limited land.

In simple terms, you may be able to take one residential lot and legally separate it into two separate lots. Each new lot can then have its own residential home and supporting structure.

This doesn’t mean every property in California can be split.

The SB-9 only applies to qualifying single-family properties. SB-9 rules can’t be used on commercial lots. Moreover, each city reviews applications based on specific eligibility requirements.

What Does SB-9 Actually Allow?

At its core, the SB-9 allows homeowners on a single-family residential lot to do two things with their property.

First is what we call an urban lot split. You can divide one residential lot into two separate parts.

Second, you get the ability to build up to four structures on what was once a single-family property. Apart from two primary homes, you may also build accessory dwelling units (ADUs) or junior accessory dwelling units (JADUs).

Key Components and Requirements of SB-9 Lot Splits

The SB-9 lot split isn’t just a simple division of land. Properties must meet specific qualifying criteria and requirements before they can be approved.

Qualifying Criteria & Requirements

Zoning: First, the property must be in a single-family residential zone. It also needs to be within an urban area, as defined by the U.S. Census Bureau.
Lot Size: Under SB-9 rules, once the parcel is split, the resulting two lots must meet certain standards. Neither lot can be smaller than 40% of the original parcel.
Access: Each new lot must have proper access to a public street. Having the right-of-way along utility access is also allowed.
Process: SB-9 projects are reviewed through a ministerial process. This means cities evaluate applications based on objective zoning standards, rather than discretionary review or public hearings.

Restrictions

Location-Based Restrictions: The property must not be within protected environmental areas. You’re also not qualified if your property is considered a historic property, located within a historic district, or within a conservation zone.
High-Risk Areas: Properties in high-risk areas aren’t eligible for the SB-9 lot split. This includes lots near fire hazard zones, fault lines, or hazardous waste sites.

Minimum Lot Size for SB-9 Lot Splits

One of the most important rules under SB-9 is the minimum lot size. Even if your property qualifies, the new parcels can’t be too small.

The SB-9 requires that the newly split lots must be roughly the same size. The split should be no smaller than 60/40.

Additionally, each resulting parcel must be at least 1,200 square feet in size. As a result, the original lot must typically be at least 2,400 square feet to support an SB-9 lot split.

What You Can Build Under SB-9

In general, you can build up to four residential units under the SB-9 rules. These include the following.

Primary Home: The primary home is the main house on the property. It can be the existing single-family home, or it can be a newly built structure.
Second Home: In some scenarios, you can build a second full-sized home on the same lot. This depends on local rules and approvals.
Accessory Dwelling Unit: An ADU is a smaller, independent living unit within the property. It usually has its own kitchen, bath, and entrance.
Junior Accessory Dwelling Unit: A JADU is an even smaller unit. It is integrated into the primary home. For instance, you can convert your garage into a new separate home.

Note that what you can build will vary depending on your actual lot size and local regulations. In many cases, site limitations and ADU/JADU rules can prevent you from building more than one primary home per lot.

Benefits of an SB-9 Lot Split

An SB-9 lot split creates new opportunities for homeowners by increasing flexibility in how a residential property can be used and developed.

Flexibility: Instead of being limited to a single residential lot, you can now divide your property into two separate parcels.
Additional Housing: You can build additional housing on the new parcel of land. This means you can accommodate family members or create separate living spaces.
Ministerial Process: Your application will be evaluated based on objective standards. There will be no public hearings or votes.