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California's housing crisis has led lawmakers to innovate. Two recent laws, SB 450 and SB 9, aim to tackle the state’s housing shortage by encouraging housing creation in areas traditionally reserved for single-family homes. Each law targets different challenges, and together they have the potential to transform urban landscapes across California.
SB 450: Subdivision Map Act Reform
SB 450, known as the Subdivision Map Act Reform, was introduced by Senator Bob Wieckowski and was passed by the California Legislature in 2023. It cleared the State Senate on May 30, 2023, followed by a vote in the State Assembly on September 7, 2023. Governor Gavin Newsom signed SB 450 into law on October 13, 2023. This law allows property owners in urbanized areas to subdivide single lots into smaller parcels more easily, streamlining the bureaucratic requirements often associated with land subdivision. Property owners can now bypass extensive environmental reviews that often stall development, creating a quicker path to new housing.
By reducing red tape, SB 450 opens up new avenues for affordable housing on a smaller scale, especially in areas where single-family zoning previously restricted density. This law is particularly significant in making land more accessible for homeowners and developers who wish to create multiple housing units, contributing to California’s broader housing goals.
SB 9: Duplex and Lot-Splitting Law
SB 9, signed into law in 2021, was authored by Senator Toni Atkins and Assemblymember Robert Rivas. Often called the "duplex law," SB 9 allows homeowners to split a single-family zoned lot into two and build up to two units on each parcel. The California Senate passed SB 9 on May 26, 2021, and it was approved by the California Assembly on August 26, 2021. Governor Newsom signed SB 9 into law on September 16, 2021. It went into effect on January 1, 2022.
SB 9 aims to create "gentle density," allowing for up to four units on what was previously a single-family lot. This incremental approach to density can help increase California’s housing supply without requiring drastic zoning changes or high-rise developments.
Complementary Goals for a Common Challenge
While SB 450 focuses on subdivision of land to make smaller parcels available, SB 9 allows for increased housing units per lot. Together, they create a cohesive framework for adding more housing in California’s urban and suburban areas, supporting what’s often referred to as “missing middle” housing.
These laws encourage affordable, diverse housing options while addressing community concerns about drastic changes to neighborhood aesthetics. By streamlining subdivision and encouraging additional units on single-family lots, California is making strides toward a more resilient housing market.
Together, SB 450 and SB 9 represent a meaningful step forward in creating accessible housing opportunities. Through these policies, California is enabling homeowners and developers to contribute to housing density within existing neighborhoods, a key component in meeting the needs of a growing population.
