ADU Regulations in California, California (2026)

Regulations at a glance

Local rules & notes

Pre-Approved ADU Plans (AB 1332): Local agencies must develop a program for the preapproval of ADU plans by January 1, 2025, and must post these plans and contact info on their websites. JADU Owner Occupancy Relaxation (AB 1154): Effective Jan 1, 2026, owner-occupancy is only required for JADUs if they share sanitation facilities with the primary structure. Unpermitted ADU Amnesty (AB 2533): Local agencies cannot deny permits for unpermitted ADUs built before Jan 1, 2020, unless there is a health/safety violation. They also cannot charge impact fees for these units if the owner is low-income. Separate Conveyance (AB 1033): Allows local agencies to adopt ordinances permitting the separate sale of ADUs as condominiums.

For the official ordinance and latest updates, check your city or county planning department.

Frequently asked questions about ADU regulations in California

• What is the maximum ADU size in California, California?

  In California, the maximum ADU size is typically 1200 square feet, depending on whether the unit is attached or detached. California state law allows up to 1,200 sq ft for detached ADUs and 800 sq ft for attached in many jurisdictions; California may follow state defaults or have local limits. Verify with California planning for your specific lot.

• What are the setback requirements for ADUs in California?

  In California, typical setback requirements are 4 feet from the side property line and 4 feet from the rear. These may be reduced to 4 feet under California Government Code § 65852.2 where applicable. Check with California planning for overlay zones or design standards that could affect your site.

• What is the maximum height for an ADU in California?

  In California, the maximum height for an ADU is generally 16 feet. State law often allows up to 16 feet for detached ADUs and up to 25 feet when within 4 feet of the property line in some cases. Confirm with California or county planning for your zone.

• Is ADU approval ministerial in California?

  In California, ADU approval is typically Ministerial (by-right) per Gov Code §65852.2. Ministerial (by-right) review means the city must approve qualifying applications without discretionary review, per California Gov Code § 65852.2. Your project must still meet objective standards; California planning can confirm the exact process.

• Are there parking requirements for ADUs in California?

  In California, parking for ADUs is generally 1. California law often waives parking for ADUs within a half-mile of transit or in certain historic districts. Check with California planning for your address.