ADU Regulations in National City, California (2026)

Regulations at a glance

Local rules & notes

Pre-Approved Plan Fast-Track: Local agencies must approve or deny applications for detached ADUs within 30 days if they use a pre-approved plan. Unpermitted Unit Amnesty: Local agencies cannot deny a permit for an unpermitted ADU built before January 1, 2020, unless it is a health and safety threat. JADU Shared Sanitation Exception: New 2026 addendum clarifies that owner-occupancy is only required for JADUs if they share sanitation facilities with the primary home.

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

Frequently asked questions about ADU regulations in National City

• What is the maximum ADU size in National City, California?

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

• What are the setback requirements for ADUs in National City?

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

• What is the maximum height for an ADU in National City?

  In National City, 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 National City or county planning for your zone.

• Is ADU approval ministerial in National City?

  In National City, 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; National City planning can confirm the exact process.

• Are there parking requirements for ADUs in National City?

  In National City, 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 National City planning for your address.