NHEH Publications

Is SB 9 the End of Single Family Zoning as We Know It?

By Heidi A. Quinn, Attorney
Noland, Hamerly, Etienne & Hoss

                                  As Published in the Salinas Valley Business Journal, December 2021

Senate Bill 9, much like the recent Accessory Dwelling Unit (“ADU”) law, is intended to create additional housing while preserving affordable units.  Effective January 1, 2022, SB 9 makes it easier to build more than one housing unit in some neighborhoods reserved for single-family homes.  Referred to as the “duplex law,” some predict entire single-family neighborhoods could transition to duplexes. Yet, the Terner Center for Housing at UC Berkeley estimates just 5.4% of single-family lots would be physically eligible and financially feasible under SB 9.  

Prior to SB 9, a homeowner could have a maximum of three homes on their single-family zoned lot – the primary residence, an ADU, and an attached junior ADU (“JADU”).  SB 9 allows for the development of new “for sale” homes, either on a newly subdivided lot or through the conversion of an existing single-family home into multiple units.  Where allowed, an owner may split an existing lot into two lots, and build two new units on each lot – resulting in four homes.  There is no affordability requirement.

Agencies will be required to ministerially approve development proposals that meet specified size and design standards (height, setbacks, and lot coverage), and may not preclude construction of at least two 800 square feet units.  In certain circumstances, agencies may require parking, easements for public services, and access to a public right-of-way.  When a lot is both created and developed with two units under SB 9, agencies are not required to also allow an ADU or JADU.  

Agencies may deny a proposal if they find the proposed project would have a “specific, adverse impact” on “public health and safety or the physical environment” and there are no feasible and satisfactory mitigation options.  Further, local restrictions, such as a lack of water or a moratorium on new connections, will limit local development under SB 9.  

SB 9 was drafted to limit the ability of developers to purchase multiple lots and negatively impact neighborhoods.  For example, a lot may only be subdivided once and an owner may not split their lot if they have already subdivided an adjacent lot.  Newly created lots must be at least 1,200 square feet, unless an agency adopts a smaller minimum lot size, and must be approximately equal in size.  Further, a subdividing owner is required to occupy a unit as a primary residence for at least three years.  New units may not be used as short-term rentals.  

Additionally, certain properties will not be eligible for SB 9 development including non-urbanized properties, historic properties, farmlands, wetlands, high fire or flood zones.  To protect housing stock, a proposed project cannot result in the demolition of affordable or rent-controlled housing or properties occupied by a tenant in the past three years.  

These requirements, along with physical constraints (small lot sizes and local regulations), and the expense of subdivision and new construction will limit the number of homes developed under SB 9.  Nonetheless, efforts to launch a ballot measure against SB 9 are underway.


This article is intended to address topics of general interest and should not be construed as legal advice.  © 2021 Noland, Hamerly, Etienne & Hoss