1 in 4 new California homes is in someone's backyard
9 hours ago
- In 2025, ADUs accounted for a quarter of all new California homes, with 41,846 permitted vs. 43,083 detached houses.
- State preemption laws stripped cities of the power to deny ADUs, requiring approval or denial within 60 days without a hearing.
- From 2018 to 2025, California cities issued ~213,000 ADU permits but only ~108,000 were completed, with some permits legalizing existing garage conversions.
- ADU construction boomed because homeowners directly benefit financially, bypassing the need for developers or subdivisions.
- SB 9, which allows lot splits or duplexes, proved far more complex: Los Angeles approved only 38 of 211 applications in its first year, compared to 7,160 ADUs.
- The author chose to build an addition instead of an ADU due to higher costs and risks of separate utility trenching and setback constraints.
- It took about 26 bills over 10 years to close city loopholes, such as owner-occupancy requirements, subjective design rules, and impact fees.
- State law bars cities from requiring replacement parking for garage conversions; a Sacramento study found over 75% of households retained sufficient off-street parking.
- ADUs represent a successful end-run around local prohibitions on infill housing, with YIMBYs pushing state preemption further.