October 25, 2021

Senate Bill 9 California: SB-9 Housing Development For Single-Family Lot

UPDATED, July 27, 2022

California Senate Bill 9 (SB-9) passed in the legislature and was signed by Governor Gavin Newsom in September 2021 (1). The changes listed in the SB-9 bill took effect sometime in January 2022 and are projected to aid in the fight against California’s housing shortage crisis. The bill works in tandem with SB-10 to streamline permitting and increase production to create more available housing at a faster pace. 

Now, let’s dig deeper into what SB-9 is and key takeaways that you should consider.


What Is Senate Bill 9

State Senator, Toni Atkins, authored Senate Bill 9 in an effort to allow owners of existing single-family lots to build as many as four housing units on their property (2). Under SB-9, lot owners have the option to split a single lot and create two separate dwellings on each, needing only the approval of ministerial officials and bypassing many of the usual regulations from local government. 


Senate Bill 9 Key Takeaways

Senate Bill 9 is very thorough, so to simplify, we’re sharing key takeaways below.

  • Local zoning agencies will be required to approve all lots meeting these qualifications:
    – the lot is a minimum of 1,200 square feet and will be split into nearly equal lots (3).
    – the lot is classified as a single-family residential.
    – the lot was not zoned prior to SB-9 and has not been deemed a historic landmark.
    – no splits by the same owner through this bill exist adjacent to the proposed lot.
    – splitting would not destroy existing affordable housing.
  • SB-9 will be applied throughout the entire state without exception.
  • Local governments will only be able to deny an application if it would have an adverse effect on public health and safety.
  • The use of provisional maps will be extended by an additional 12 months.

The key component of this bill is the new limitations set on local government. For example, SB-9 prohibits most of the typical objective standards regulating design, zoning, and subdivision that would hinder construction on a unit up to 800 square feet. 


SB-9 Housing Development Guidance

senate bill 9 california pasquini engineering article - Senate Bill 9 California: SB-9 Housing Development For Single-Family Lot - blog

The Legislative Counsel’s Digest of SB-9 is dense and extensive. The key takeaways give you an idea of what you can accomplish, but the intricacies of the bill in action can be complex and even painstaking. 

As a top engineering firm in California, Pasquini Engineering, Inc. associates will help to alleviate frustration and  guide you through SB-9 compliance during development from start to finish. We serve several locations throughout California and offer services in building design, site civil engineering, and structural engineering with more than 30 years of experience. As a dedicated team that is well-versed in the qualifications of housing development, we can help you through every step of the Senate Bill 9 process to avoid missed opportunities and eliminate disqualifying mistakes. 


SB-9 And SB-10 California

While SB-9 and SB-10 are both designed to ease the state’s housing crunch by opening more areas to high-density housing developments, they address different parts of the equation. Whereas SB-10 gives city government greater flexibility in planning and zoning, SB-9 allows private landowners to build additional housing on parcels originally zoned for single-family homes.

Learn more about Senate Bill 10, and how it’ll will make it easier for municipalities across the state to create high-density housing by lifting zoning restrictions



Senate Bill 9 and 10 present many opportunities for homeowners, residential landowners, and the housing development industry. Developers can take advantage by fast-tracking their plans to create affordable housing when it is needed the most. So, if you are looking to get started with SB-9 housing development, contact us today and we’ll get you started on the right path. 


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