Del Mar ADUs and the coastal permit

Most Del Mar ADUs need an Administrative Coastal Development Permit, but not all. Chapter 30.91 spells out the exemptions and the process (Del Mar Municipal Code Chapter 30.91 (June 2025)).

Exempt from a CDP

• Conversion of entirely existing, legally established habitable space in the house, without removing or replacing roofs, exterior walls or foundations
• An ADU directly attached to an existing single-family house that qualifies as exempt under Coastal Commission regulation §13250

The administrative CDP process

1. Staff provide a notice card posted at the site; plans are available at City Hall
2. No public hearing
3. The Planning and Community Development Director finds the ADU consistent with the certified LCP and Coastal Act access policies
4. Notice of approval posted at City Hall and online, mailed within five working days to owners within 300 ft and occupants within 100 ft
5. Notice sent to the Coastal Commission San Diego Coast District
6. If appealable, the decision may be appealed to the Coastal Commission within ten working days

When ministerial approval isn't available

Expanding water wells, sewer, fire protection capacity or septic systems, or significantly altering landforms, takes the project out of ministerial approval.

State timelines in the Coastal Zone

Where a certified Local Coastal Program has ADU provisions, as Del Mar's does, the HCD handbook says the city must approve or deny a coastal development permit for an ADU within 60 days of a complete application when there's an existing primary dwelling, without a public hearing, and concurrently with the ADU decision. State ADU law applies in the Coastal Zone but doesn't lessen Coastal Act resource protections.

Is your lot in the appeal zone?

Del Mar's application asks whether the parcel is in the Coastal Commission's appeal jurisdiction, and the ADU verification form asks whether the property lies between the ocean and the first public roadway. Expect those questions at intake; they affect notice and appeal options.

Other questions on the application

• Is the parcel in or next to a wetland, floodplain, beach, wildland urban area or other sensitive area?
• Are there open code enforcement cases?
• Will existing nonconformities (setbacks, floor area, parking) remain?
• Is any work proposed in the public right-of-way?

Walkthrough

1. Confirm whether an exemption applies (attached ADU, or conversion without replacing roofs, walls or foundations).
2. Submit the Uniform Development Application, ADU Verification Form and engineering package.
3. City review runs concurrently for the ADU and the CDP.
4. Notice of approval, then building permits.

Also checked Oct 14, 2026: Del Mar ADU Application Packet (Rev. 2024) · HCD ADU Handbook (March 2026).

Sources, checked Oct 14, 2026: Del Mar Municipal Code Chapter 30.91 (June 2025).