Proposed Single-Family Zoning Reform Would Have a Big Footprint in California

SB 1120 is the latest law proposed in the California Legislature to preempt restrictive local zoning.

2 minute read

August 17, 2020, 12:00 PM PDT

By James Brasuell @CasualBrasuell


South Bay Area

Alexey Ulashchick / Shutterstock

The Terner Center for Housing Innovation has published a detailed analysis of SB 1120, a law proposed in California as the latest attempt to ease development restrictions and spur housing development in the infamously expensive state.

The effect of SB 1120 would be similar to similar planning innovations in the cities of Minneapolis and Portland, as well as the state of Oregon: to end the exclusionary regulations of vast swaths of single-family zoning

As written, SB 1120 affects single-family parcels in two ways that could ultimately lead to up to four homes on lots where currently only one exists. First, the proposed legislation would allow existing single-family homes to be converted into duplexes. Second, the proposed legislation would allow single-family parcels to be subdivided into two lots, while also allowing for a new, two-unit building to be constructed on the newly formed lot.

While the paper predicts the potential for the proposed law to facilitate the construction of a significant number of new units in the state, the final total would be determined by local regulations and financing opportunities. 

The analysis includes an assessment of the number of parcels statewide that would be eligible to split as defined by the bill's current language. According to the paper, millions of parcels would be eligible to split— 5,977,061 to be exact. In a state with about 12.5 million parcels in total, that would be a significant amount of potential change.

Friday, July 31, 2020 in Terner Center for Housing Innovation

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Get top-rated, practical training

Close-up of "Apartment for rent" sign in red text on black background in front of blurred building

Trump Administration Could Effectively End Housing Voucher Program

Federal officials are eyeing major cuts to the Section 8 program that helps millions of low-income households pay rent.

April 21, 2025 - Housing Wire

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

April 30, 2025 - Diana Ionescu

Close-up on Canadian flag with Canada Parliament building blurred in background.

Canada vs. Kamala: Whose Liberal Housing Platform Comes Out on Top?

As Canada votes for a new Prime Minister, what can America learn from the leading liberal candidate of its neighbor to the north?

April 28, 2025 - Benjamin Schneider

Washington

Washington State’s Parking Reform Law Could Unlock ‘Countless’ Acres for New Housing

A law that limits how much parking cities can require for residential amd commercial developments could lead to a construction boom.

6 hours ago - Streetsblog USA

Bluebird sitting on branch of green bush.

Wildlife Rebounds After the Eaton Fire

Following the devastation of the Eaton Fire, the return of wildlife and the regrowth of native plants are offering powerful signs of resilience and renewal.

7 hours ago - AP News

1984 Olympics

LA to Replace Inglewood Light Rail Project With Bus Shuttles

LA Metro says the change is in response to community engagement and that the new design will be ready before the 2028 Olympic Games.

May 1 - Newsweek

Urban Design for Planners 1: Software Tools

This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.

Planning for Universal Design

Learn the tools for implementing Universal Design in planning regulations.