ADU Regulations in Butte County, California (2026)

Regulations at a glance

Local rules & notes

Agricultural Buffer Area Restriction: The County ordinance attempts to preclude ADUs in a 300-foot buffer zone adjoining Agriculture parcels. HCD ruled this invalid for state-exempt ADUs. Existing Second Unit Ban Overruled: The County tried to prohibit new ADUs if a lot already had a 'second unit' (built 1995 or later). HCD clarified that owners are entitled to an ADU and JADU regardless of existing non-conforming zoning conditions. Missing Unpermitted ADU Legalization Program: State law requires the county to inform the public about permitting unpermitted ADUs (Section 66332), but HCD could not locate these resources.

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

Frequently asked questions about ADU regulations in Butte County

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

  In Butte County, 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; Butte County may follow state defaults or have local limits. Verify with Butte County planning for your specific lot.

• What are the setback requirements for ADUs in Butte County?

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

• What is the maximum height for an ADU in Butte County?

  In Butte County, 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 Butte County or county planning for your zone.

• Is ADU approval ministerial in Butte County?

  In Butte County, 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; Butte County planning can confirm the exact process.

• Are there parking requirements for ADUs in Butte County?

  In Butte County, parking for ADUs is generally Often waived per state law; check local ordinance. California law often waives parking for ADUs within a half-mile of transit or in certain historic districts. Check with Butte County planning for your address.