ADU Regulations in Placer County, California (2026)

Regulations at a glance

Local rules & notes

Affordability Fee Exemption: ADUs and JADUs can qualify for a full development fee exemption if they are deed-restricted for affordability as verified by the County. Outdoor Covered Area Limitation: Covered porches and decks attached to an ADU are limited to 25% of the allowable living area of the unit. Williamson Act Land Restrictions: Specific limitations apply to ADUs on lands subject to Williamson Act contracts, requiring them to support on-site agricultural operations.

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

Frequently asked questions about ADU regulations in Placer County

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

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

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

  In Placer County, typical setback requirements are 5 feet from the side property line and 5 feet from the rear. These may be reduced to 4 feet under California Government Code § 65852.2 where applicable. Check with Placer County planning for overlay zones or design standards that could affect your site.

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

  In Placer 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 Placer County or county planning for your zone.

• Is ADU approval ministerial in Placer County?

  In Placer 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; Placer County planning can confirm the exact process.

• Are there parking requirements for ADUs in Placer County?

  In Placer County, 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 Placer County planning for your address.