California residential & ADU permit data

California runs the most far-reaching accessory-dwelling-unit framework in the country, built up through a decade of bills now consolidated in Government Code section 66310 and following (recodified in 2025 from the former section 65852.2). A 2019 package — SB 13, AB 68 and AB 881 — forced local governments to approve a conforming ADU ministerially, without a public hearing or discretionary review, and to act within 60 days of a complete application. Cities must allow at least one ADU plus one junior ADU on most single-family lots, cannot use minimum-lot-size rules to block them, and must permit an ADU of at least 800 square feet regardless of local floor-area, lot-coverage or setback limits that would otherwise prevent it.

The same package stripped away the biggest local 'ADU killers.' Off-street parking cannot be required when the ADU is within half a mile of transit, when it is a conversion of existing space, or in several other common situations, and impact fees are waived entirely for units under 750 square feet and capped proportionally above that. AB 976 (2023) made the ban on owner-occupancy requirements permanent for ADUs permitted on or after January 1, 2025, so an owner can rent out both the main house and the ADU — though junior ADUs still carry an owner-occupancy condition.

Two newer laws push the market further. AB 1033 (2023) lets a city opt in to allowing an ADU to be sold separately from the main home as a condominium, and SB 1211 (2024) raised the cap on detached ADUs at existing multifamily properties to as many as eight and barred cities from forcing the replacement of uncovered parking removed to build them.

ADUs sit alongside California's broader 'missing middle' reforms — SB 9 (2021) ministerial duplexes and urban lot splits, and the transit-oriented SB 79 phasing in from 2026 — so a single-family parcel can often support several new units by right. That layering, plus Igni's structured SB-9 and SB-10 corridor flags on live Los Angeles, San Francisco, San Diego and Anaheim permit data, is what makes California the deepest ADU pipeline in the US.

This is an informational summary, not legal advice; ADU rules change frequently and local ordinances add detail, so confirm the current state statute and your city's rules before relying on it.