ADU Regulations in Riverside County, California (2026)

Regulations at a glance

Local rules & notes

Two-Story Allowance: Riverside allows ADUs to be two stories and up to 35 feet, significantly higher than the state-mandated minimums of 16-18 feet. Nonprofit Separate Sale Exception: While standard ADUs cannot be sold separately, there is a specific carve-out for nonprofit affordable housing organizations. JADU Efficiency Unit Minimum: The city defines a minimum size for JADU efficiency units at 220 square feet.

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

Frequently asked questions about ADU regulations in Riverside County

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

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

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

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

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

  In Riverside County, the maximum height for an ADU is generally 35 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 Riverside County or county planning for your zone.

• Is ADU approval ministerial in Riverside County?

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

• Are there parking requirements for ADUs in Riverside County?

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