Tiny Home Laws in California

Navigate the legal landscape for building and living in tiny homes across the state.

County-by-County Legal Status of Tiny Homes on Wheels (THOWs) in California (2025)California's statewide laws (e.g., Appendix Q of the California Building Code and ADU regulations under Government Code Section 65852.2) generally allow THOWs as Accessory Dwelling Units (ADUs) or primary residences if they meet standards like ANSI 119.5 certification, DMV registration as a vehicle, size limits (typically 150–400 sq ft), and local zoning compliance. THOWs are often treated as RVs for short-term use but can be permanent if skirted, connected to utilities, and permitted. However, local ordinances vary—always verify with the county planning department for the latest.

Below is an alphabetical table summarizing THOW status for all 58 counties, based on 2025 data.

Good news for tiny home enthusiasts: California is one of the most THOW- and ADU-friendly states in 2025. Recent legislation, including over 60 new housing bills effective January 1, has streamlined permitting, reduced fees, and expanded where you can place your tiny home. No more red tape—focus on building!Key 2025 Regulations at a Glance

ADUs (Accessory Dwelling Units): Tiny homes under 1,200 sq ft can now be built as ADUs on single-family lots without owner-occupancy requirements in most cities. No minimum lot size, and parking mandates are waived near transit.
Zoning & Placement: Allowed in residential zones statewide; THOWs count as single-family dwellings if permitted. Coastal areas like Santa Cruz cap size at 400 sq ft and height at 14 ft, but inland spots (e.g., Nevada County) are more flexible.
Building Codes: Must meet Title 24 energy standards and seismic requirements. Park model RVs (under 400 sq ft) are exempt from some inspections if HUD-certified.
New 2025 Changes: SB 477 lowers impact fees by 50% for ADUs under 750 sq ft and allows multi-unit ADUs on multifamily lots. Tiny homes on wheels can now park long-term in backyards as second units.

Where Can You Put Your Tiny Home?
Most residential zones welcome them as ADUs—urban backyards, rural lots, or even RV parks. Check local ordinances via your city's planning department, but state law overrides restrictive rules. Pro tip: Start with a pre-approved design to speed up permits (often 30–60 days).Quick Checklist for Compliance

Secure building permit ($500–$2,000 avg.)
Verify foundation (permanent) or wheels (mobile)
Install smoke/CO detectors and egress windows
Consult HCD's ADU Handbook for free templates

Questions? Download the full 2025 ADU Handbook or contact your local AHCD office.