Legal Guide · California

California ADU Laws 2025: What Changed and What to Know

Your up-to-date overview of statewide ADU rules for 2025 — approvals, size & height limits, parking, owner-occupancy, and emerging local options for condo-sale ADUs.

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Quick table of contents
  1. What’s new in 2025
  2. Core statewide rules
  3. Multifamily ADUs
  4. Permits & timelines
  5. City highlights (LA, San Diego, San José, SF)
  6. FAQ
  7. Official resources
TL;DR: In 2025, California continues streamlined ADU approvals with ministerial review, consistent minimum size and setback protections, broad parking exemptions, and no state-mandated owner-occupancy for standard ADUs. Some cities allow separate ADU sale (AB 1033) by local ordinance — always confirm locally before planning a split-sale.
Backyard ADU beside a main house at sunset with native landscaping

What’s new in 2025 (vs. 2024)

Topic20242025
Owner-occupancy Temporary waivers widely applied. Permanent ban on owner-occ for ADUs statewide (JADUs may be different if specified). (Gov. Code § 66315.)
Ministerial timelines 60-day “approve or deny.” Still 60 days — now expressly deemed approved if a complete application isn’t approved or denied in time. (Gov. Code § 66320.)
Parking replacement No replacement when garages/carports converted. Now also no replacement for uncovered spaces demolished for an ADU. (Gov. Code § 66314(d)(11).)
Multifamily detached ADUs Up to 2 detached per lot. Up to 8 detached on lots with an existing multifamily dwelling (not to exceed the number of existing units); up to 2 on lots with a proposed multifamily dwelling. (Gov. Code § 66323.)
Statute numbering Primarily § 65852.2, etc. Renumbered into §§ 66310–66342 (SB 477) for clarity.

State law sets minimums. Cities can be more permissive but not more restrictive; always verify local bulletins before applying.

Core statewide rules (quick overview)

Size & setbacks

  • At least one 800 sq ft ADU must be allowed on most lots, subject to building/safety codes.
  • 4′ side & rear setbacks for new detached ADUs (typical state minimum).
  • JADU up to 500 sq ft within the SF home or accessory structure.

Height (state minimum allowances)

  • 16 ft minimum for a detached ADU on most lots.
  • 18 ft if near transit (½-mile walking) or on lots with existing/proposed multifamily, multistory buildings; +2 ft to match roof pitch.
  • Up to 25 ft (or primary home’s limit) for an attached ADU. (Gov. Code § 66321(b)(4).)

Parking

  • No parking required within ½-mile of transit, when the ADU is within/attached to the home, and other statute scenarios.
  • No replacement required when a garage/carport/covered or uncovered space is removed for an ADU. (Gov. Code § 66314(d)(11).)

Processing

  • Ministerial (objective standards only) per state law.
  • Agency must approve/deny a complete application in 60 days or it’s deemed approved. (Gov. Code § 66320.)

Multifamily ADUs (duplexes, apartments)

As of 2025, multifamily properties have expanded by-right options:

  • Detached ADUs (existing MF): up to 8 per lot, not exceeding the number of existing units.
  • Detached ADUs (proposed MF): up to 2 per lot.
  • Conversion ADUs: within non-livable space; at least one is allowed and up to 25% of existing units.
  • Typical minimums: 4′ side/rear setbacks and 18 ft height for detached MF ADUs under § 66323.

Note: “66323 Units” are state-mandated categories that must be approved ministerially and are exempt from many local standards beyond those listed in § 66323.

Permits & timelines

1) Feasibility — confirm zoning, utilities, overlays (hillside/coastal), and objective standards.
2) Design & drawings — site, floor/elevations, Title-24/energy, structural as needed.
3) Submittal — apply for ministerial approval; include the objective-standards checklist.
4) Corrections — respond to plan check comments (objective only).
5) Approval & fees — permit issuance; school/utility/impact fees as applicable.
6) Build & inspections — foundations (if new), framing, MEP rough/finish, final.

Statutory clock: a complete application must be approved/denied in 60 days or is deemed approved. (Gov. Code § 66320.)

City highlights (2025 changes to watch)

Los Angeles

  • Follows state minimums: at least 800 sq ft, 4′ setbacks, ministerial review.
  • Standard Plan Program of pre-approved ADU designs via LADBS to speed permitting.
  • Short-term rentals restricted under Home-Sharing; many ADUs effectively limited to 30+ days. Verify eligibility/registration.

Official links: LADBS Standard Plans · Home-Sharing

San Diego

  • Condo-sale ADUs enabled: Ordinance O-21989 (effective Aug 22, 2025 outside the Coastal Zone) implements AB 1033.
  • Broad parking flexibilities continue; check coastal overlays.
  • Active ADU guidance via Development Services.

Official links: Ordinance O-21989 (PDF) · Info Bulletin 400

San José

  • First CA city to implement AB 1033 and approve an ADU condominium in 2025.
  • Runs a robust Preapproved ADU Plans program.

Official links: City news release · Preapproved ADUs

San Francisco

  • Condo-sale ADUs: Ordinance 113-25 adopted July 8, 2025 (implementation details apply).
  • ADUs generally ineligible for short-term rentals under SF rules.

Official links: Ord. 113-25 (PDF) · SF Planning ADUs

Planning outside these cities? Start with the statewide rules, then check your city’s planning portal for any local objective standards, overlays, or implementation bulletins.

Next up: we’ll add deep-dive city playbooks under Los Angeles, San Diego, San Francisco, and others as they’re verified.

Official resources (start here)

California ADU law FAQs (2025)

Do I need to live on-site to build an ADU?

No. State law prohibits owner-occupancy requirements for ADUs. Some cities may require owner-occupancy for JADUs. (Gov. Code § 66315.)

How big can my ADU be?

At least one ADU up to 800 sq ft with 4′ side/rear setbacks must be allowed when meeting building/safety codes. Larger sizes may be permitted locally. (Gov. Code § 66323(a)(2)(A).)

What about height limits?

Minimum state allowances include 16 ft for detached ADUs (most lots), 18 ft near transit or on lots with multifamily multistory buildings, and up to 25 ft for attached ADUs (or the primary home’s height limit, whichever is lower). (Gov. Code § 66321(b)(4).)

Is parking required?

Often no. Parking cannot be required within ½-mile of transit or for units within/attached to the home. Replacement is not required for garages, covered, or uncovered spaces removed for an ADU. (Gov. Code §§ 66322(a), 66314(d)(11).)

Can I sell my ADU separately as a condo?

Sometimes. AB 1033 lets cities adopt an ordinance to allow separate sale via condo mapping. Examples: San José (first adopter), San Diego (Ord. O-21989, effective Aug 22, 2025 outside the Coastal Zone), San Francisco (Ord. 113-25, July 8, 2025). Check your city’s rules.

Are short-term rentals allowed in ADUs?

Many cities require 30+ day rentals for ADUs. Always verify your municipal code (and any home-sharing program) before listing.