ADU Regulations in Brea, California (2026)

Regulations at a glance

Local rules & notes

Building Separation Requirement: A minimum separation of 10 feet is required between the main dwelling unit and a detached ADU, even for units up to 800 square feet. Certificate of Compatibility: ADUs exceeding 850 sq ft (1 bedroom) or 1,000 sq ft (2 bedrooms) require a discretionary 'Certificate of Compatibility' review rather than ministerial approval. Pre-Approved Plans Program: The city has a program to develop pre-approved construction plans to streamline the building permit process. Short-Term Rental Prohibition: ADUs are explicitly prohibited from being used as short-term rentals, requiring a covenant.

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

Frequently asked questions about ADU regulations in Brea

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

  In Brea, the maximum ADU size is typically 1000 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; Brea may follow state defaults or have local limits. Verify with Brea planning for your specific lot.

• What are the setback requirements for ADUs in Brea?

  In Brea, 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 Brea planning for overlay zones or design standards that could affect your site.

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

  In Brea, 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 Brea or county planning for your zone.

• Is ADU approval ministerial in Brea?

  In Brea, 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; Brea planning can confirm the exact process.

• Are there parking requirements for ADUs in Brea?

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