ADU Regulations in Plymouth, California (2026)

Regulations at a glance

Local rules & notes

Family-Only Occupancy Restriction: Accessory apartments are strictly limited to immediate family members of the property owner. Detached ADU Prohibition: The code explicitly forbids accessory apartments in detached structures. Annual Notarized Affidavit: Owners must re-certify compliance every year via a notarized statement or the permit expires.

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

Frequently asked questions about ADU regulations in Plymouth

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

  In Plymouth, the maximum ADU size is typically 700 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; Plymouth may follow state defaults or have local limits. Verify with Plymouth planning for your specific lot.

• What are the setback requirements for ADUs in Plymouth?

  In Plymouth, typical setback requirements are 15 feet from the side property line and 50 feet from the rear. These may be reduced to 4 feet under California Government Code § 65852.2 where applicable. Check with Plymouth planning for overlay zones or design standards that could affect your site.

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

  In Plymouth, the maximum height for an ADU is generally 30 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 Plymouth or county planning for your zone.

• Is ADU approval ministerial in Plymouth?

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

• Are there parking requirements for ADUs in Plymouth?

  In Plymouth, 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 Plymouth planning for your address.