SB9 Lot Split : Detail Guide

In recent years, California has been grappling with a pressing need for affordable housing solutions and increased housing density. In response to this growing concern, the state has implemented several housing regulations, including Senate Bill 9 (SB 9) which introduces the concept of (SB9) lot splitting

Shortage of affordable homes in California

Why does this happen?

It is mainly because of the state’s housing crisis. In his article “The California Housing Crisis: Where We Started and Where We’re Going” Sydney Schoeller explains, “Access to affordable housing, however, is becoming increasingly unattainable for many Americans. Last year, rates of chronic homelessness increased by 20%, nearly a million people were evicted, homeless camps continued to expand across the country

To address the issue of affordable housing, the government has introduced bills such as SB9, SB886, and AB2097. These bills aim to implement measures that ensure accessible housing options for everyone.

What is The SB9 Rule in California?

The SB9 rule in California refers to Senate Bill 9, a piece of legislation that was passed to address the housing shortage and promote infill development in the state. 

SB9 allows property owners to split their single-family residential lots into two separate lots, each of which can be developed with a residential unit. This means that a single lot can potentially accommodate two homes. The legislation also includes provisions for building accessory dwelling units (ADUs) on the newly split lots. 

SB9 Rule in California

Importance and Relevance Of SB9 Lot Split in Real Estate

By allowing property owners to split their lots, it creates opportunities for the construction of additional housing units, potentially doubling the number of homes on a single lot. This can help alleviate the housing affordability crisis and provide more options for prospective homebuyers.

Importance and Relevance Of SB9 Lot Split

According to data from the California Department of Housing and Community Development, as of 2021, the state needs to build an estimated 1.8 million new housing units by 2025 to keep up with demand. 

Secondly, the legislation promotes infill development, which encourages the efficient use of existing infrastructure and resources. Instead of expanding into undeveloped areas, SB9 Lot Split enables the development of new housing within already established neighborhoods. This can help reduce urban sprawl and preserve open spaces.

Before SB9 lot spllit and after SB9 lot split

A report by the Terner Center for Housing Innovation at UC Berkeley found that “allowing for lot splits and increased density in single-family zones can lead to a substantial increase in affordable housing production. The report estimates that “implementing policies similar to SB9 could result in the creation of approximately 700,000 additional housing units statewide.

Furthermore, SB9 Lot Split can have positive economic impacts. Increased housing supply can stimulate the construction industry and generate employment opportunities. 

You can see “Senate Bill 9 Parcel Development Funnel (Total Numbers) from 2021 Terner Analysis”

Senate Bill 9 Parcel Development Funnel

It can also contribute to local tax revenues, benefiting municipalities and supporting public services.

SB9 lot split contribute to local tax revenues

What are The Eligibility Criteria For SB9 Lot Split?

Eligibility Criteria For SB9 Lot Split

To be eligible for an SB9 lot split, the property must meet the following criteria:

◉ It should be zoned for single-family residential use.

◉ It must be situated in an urban area or cluster.

◉ The property should have a minimum size of 2,400 square feet.

◉ There should be no tenant evictions within the last fifteen years.

◉ The property should not be located on wetlands, prime farmland, floodplain/floodways, conservation areas, habitat areas for protected species, hazardous waste sites, high or very high fire severity zones, coastal zones, earthquake fault zones, or historic districts.

◉ It should not have been previously split using SB9.

The article "How to Evaluate a Property's SB 9 Potential" discusses conducting a thorough investigation of factors to consider, as well as identifying elements to avoid and outlining the subsequent steps for assessing your property's SB 9 potential.

Restrictions May Limit the Applicability of Senate Bill SB9 Lot Split

SB9 lot split restrictions

There are several potential restrictions that may limit the applicability of Senate Bill Lot Split. Some common restrictions include:

Local Zoning Regulations:

Local municipalities may have specific zoning regulations that determine lot sizes, setbacks, density limits, or other requirements that could affect the ability to split a lot.

SB9 lot split Local Zoning Regulations

Preservation or Conservation Areas:

If the property is located in a designated preservation or conservation area, there may be restrictions on lot splitting to protect natural resources or historic features.

According to the department of planning and development of Santa Clara, “historic sites or districts sites, prime farmland, wetlands, Habitat for protected species, Lands under conservation easement are Ineligible for SB 9.”

Environmental Considerations:

Environmental regulations and considerations, such as wetlands, endangered species habitats, or other ecological factors, can restrict lot splitting. “The state government code goes on to say that exemptions can be made for sites that have adopted sufficient fire hazard mitigation measures. So if your proposed development meets specific fire safety requirements, your property may be eligible for SB 9.” According to the article, SB 9 in Very High Fire Severity Zones

Infrastructure Limitations:

The availability and capacity of infrastructure such as roads, utilities, and services may impact the feasibility of lot splitting. In his article, “California’s Crumbling Infrastructure: An Urgent Priority”,José Cisneros wrote that , “Approximately 83% of Californians live, work and play in cities. As the state has struggled to balance its budget, it has cut infrastructure funding programs and taken local revenues. “

california infrastructure

HOA or Covenants:

If the property is subject to a homeowners association (HOA) or specific covenants, conditions, and restrictions (CC&Rs), there may be provisions that prohibit or limit lot splitting.

Legal or Title Constraints:

Legal constraints or title issues, such as easements, encroachments, or other property rights, may prevent or complicate lot splitting.

How to Apply For SB9 Lot Split

To apply for an SB9 lot split, follow these general steps:

How to Apply For SB9 Lot Split

Research Local Requirements: 

Research Local Requirements for SB9 lot split

SB 9 does not mandate local agencies to approve a map that would result in more than two lots or more than two units on a lot through a lot split under Government Code section 66411.7. 

Additionally, Government Code section 66411.7 stipulates that a parcel can only be subdivided once, preventing individuals from pursuing multiple lot splits over time with the intention of creating more than two lots. 

Furthermore, SB 9 does not compel local agencies to approve a lot split if an adjacent lot has previously undergone a lot split by the same property owner or someone acting in concert with them.

Gather Necessary Documentation:

Document requirements vary depending on the city or county where the property is located.

Necessary Documentation for SB9 lot split

However, here is a general list of documents that may be required:

◉ Lot Split Application Form

◉ Certificate of Occupancy

◉ Accurate survey of the property showing boundaries, dimensions, existing structures, and other relevant details

Legal description of the property such as a metes and bounds description or a reference to a recorded parcel map

◉ Copies of the property's title documents, including the deed and any recorded easements or encumbrances

◉ Detailed site plans including the division of boundaries, dimensions, access points, setbacks, and any required infrastructure improvements

◉ Owner Occupancy Affidavit

◉ Additional documents such as environmental impact reports, geotechnical studies, architectural plans, and any other information deemed necessary by the local jurisdiction

Depending on your local regulation and property characteristics, you may also required,

◉ Certified Tree Report

◉ Soils Report

◉ Photos of the property

◉ Land Records Map

◉ Grant Deeds

◉ Habitat Statement Form

SB 9 Urban Lot Split Checklist

Submit the Application:

After completing your lot split application, you are ready to submit it for review. Typically, the City Planning Department is the authority responsible for evaluating lot split applications. However, it's essential to verify the specific department in charge with your local jurisdiction.

Note - SB 9 lot splits and two-unit developments may be overseen by different departments. For example, in Los Angeles, lot splits are handled by the City Planning Department, while two-unit developments are managed by the Los Angeles Department of Building and Safety (LADBS). If your SB 9 project includes both a lot split and a two-unit development, separate applications may be required for each department.

Pay Application Fees:

In most cities, when undertaking an urban lot split, there are typically several fees that need to be paid. 

These fees can vary depending on the jurisdiction and may include,

◉ Parcel Map Fee

◉ Impact Fee, Park Fee

◉ Recordation Fee

The specific fees required will depend on the guidelines and regulations set by the local authorities. If you are planning to pursue SB 9 development on either of the resulting lots, it is important to note that additional fees will likely be necessary in conjunction with your building permit application.

Follow Up and Await Approval:

Your city will notify you in case your application is incomplete. In such a situation, you will need to rectify any necessary errors before resubmitting. The duration of the permitting process can vary, typically ranging from a few weeks to a few months.

Please be aware that if you desire a faster progression of the process, you may consider hiring a permit expediter. These individuals specialize in expediting the review and approval of lot split applications. However, it's important to note that their services can be expensive, with costs potentially reaching as high as $20,000 depending on the complexity of the project and the jurisdiction involved.

Frequently Asked Questions About SB9 Lot Split

What size lot can be split in sb9?

The local agency is mandated to allow a maximum of two primary units on the subject parcel. In the case of a lot split, each resulting parcel can also have up to two primary units. 

SB9 lot size split

Furthermore, each primary unit must be a minimum size of 800 square feet as stipulated by the local agency.A Junior Accessory Dwelling Unit (ADU) refers to a unit that is entirely located within a single-family residence and has a size limit of 500 square feet.

Are SB 9 Lot Splits Better Than Duplexes?

Comparing SB 9 lot splits to duplexes to determine which is better depends on various factors. SB 9 lot splits can optimize land utilization by creating two separate single-family homes on one lot, accommodating multiple households and providing more flexibility and customization opportunities. 

According to a survey of real estate trends, lot splits have gained popularity, with a 32% increase in applications in the past year. 

On the other hand, duplexes offer the advantage of having two rental units within a single structure, potentially generating dual income streams. Data on rental market performance shows that duplexes have maintained steady demand, with a consistent occupancy rate of over 90% and a 5% year-on-year rental income growth. 


SB9, also known as the Lot Split bill, is expected to have a significant future impact on housing in California. By allowing property owners to divide their lots and build duplexes, it aims to increase housing supply and density. This could help address the housing shortage and potentially lead to the creation of more affordable housing units. The bill may also promote efficient land use and community development. However, challenges like opposition from communities and potential effects on rental prices remain uncertain.

Element Homes, as a custom home builder in California, can assist homeowners in building homes according to SB9.  Find out more about SB9 Key challenges and benefits for homeowners in California by clicking on this link.

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