Del Mar Zoning and ADU Guide for Homeowners

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team.

Accessory dwelling units, guesthouses and converted garages affect how a Del Mar property is valued and sold. A legal unit can add rental income and buyer appeal. An unpermitted one can create disclosure duties and trouble with appraisers and lenders.

This guide summarizes the standards in Chapter 30.91 of the Del Mar Municipal Code as published by the city in June 2025, explains how the coastal and overlay rules shape what can be built, and describes what to do with an existing unit when you decide to sell.

Del Mar ADU rules at a glance

Topic	What the municipal code says
ADU size	The city accommodates at least 800 sq ft; interior floor space may not exceed 850 sq ft, or 1,000 sq ft if the ADU has more than one bedroom; an attached ADU is limited to 50 percent of the primary dwelling’s habitable space
Junior ADU (JrADU)	No more than 500 sq ft
Detached height	16 feet; 18 feet within one-half mile walking distance of a major transit stop or high-quality transit corridor
Attached height	16 feet at the first story; 25 feet or the base zoning limit, whichever is lower, for a second-story attached ADU, and no more than two stories
Bluff, Slope and Canyon Overlay	The overlay’s 14-foot maximum height applies
Side and rear setbacks	Four feet for a new ADU structure, with front setbacks of the zone still applying unless needed for an 800 sq ft unit
Units per lot	One ADU and one JrADU on a lot with a single dwelling
Rentals	Rental terms must be longer than 30 consecutive days in residential zones
Review deadline	The city ministerially approves or denies a complete building permit application within the time periods set by state law, 60 days in most cases

These numbers come from the city’s published ordinance text. The city updates its housing rules from time to time, so confirm the current version with Planning before relying on a number for a specific lot.

Size, height and setbacks

The code sets a floor and a ceiling. The city must accommodate an ADU of at least 800 square feet, and the interior floor space inside the exterior walls generally may not exceed 850 square feet, or 1,000 square feet if the unit has more than one bedroom.

An attached ADU is capped at 50 percent of the habitable space of the primary dwelling, and the code refers to a 500-square-foot bonus unit tied to the city’s incentive program. A junior ADU is a smaller unit, no more than 500 square feet.

Height limits depend on the type of unit and its location. A detached ADU may not exceed 16 feet above grade, or 18 feet near major transit.

An attached ADU that shares a wall at the first story is limited to 16 feet, and a second-story attached ADU may reach 25 feet or the base zone limit, whichever is lower, in no case more than two stories.

Inside the Bluff, Slope and Canyon Overlay Zone, the overlay’s 14-foot height limit applies instead.

A new ADU structure needs a four-foot side and rear setback, and roof eaves, cantilevers and overhangs may not encroach into it. The front setbacks of the zone still apply unless they would block an 800-square-foot unit. In Del Mar, extra coastal setbacks may also apply, including those for the Coastal Bluff Overlay, the Beach Overlay and wetland or habitat buffers.

Coastal permits, historic districts and trees

Del Mar’s ordinance says ADUs must comply with the California Coastal Act and the city’s Local Coastal Program. Approval generally requires an Administrative Coastal Development Permit unless a specific exemption applies.

The code adds standards for geotechnical reports on coastal bluffs, protection of native trees at the dripline and protection of public scenic views.

If the property is in a designated historic district or listed on a historic register, the ADU design must be consistent with the Secretary of the Interior’s Standards. For a seller, these provisions explain why an addition that looks simple can take longer than expected.

Parking

Parking rules are narrower than many owners expect. Replacement off-street parking is required when a garage or carport is converted only if the loss significantly affects public access to the shoreline. No off-street parking is required for an ADU within one-half mile of a major transit stop.

Properties along the shoreline or on the hillside in high wildfire risk areas generally must provide one off-street space, subject to exemptions such as a unit inside the primary dwelling or an existing accessory building, a historic district or a location outside the Coastal Commission appeals area.

An ADU on a site reached by a street 20 feet wide or narrower must also provide one space.

How many units are allowed

A lot with an existing or proposed single dwelling may have one ADU and one JrADU. A lot with two existing dwellings may have up to two ADUs.

On a lot with three or more dwellings, conversions of existing space are limited to 25 percent of the existing units, and up to two detached ADUs are allowed in addition.

Beginning January 1, 2025, the code says the owner must live on the property in the primary dwelling, the ADU or the JrADU for newly created units.

Fees

ADUs are subject to the city’s general application and permit fees for planning and engineering review.

The code says an ADU is not treated as a new residential use when calculating utility connection fees, although state law allows a proportionate connection fee for a unit that is not inside the existing home or an existing accessory building.

Converting space inside an existing structure with the appropriate meter size does not trigger new water and sewer connection fees.

The city’s ADU Incentive Program describes partial or full reimbursement of permit fees, plan preparation costs and code enforcement fines for participating owners, and its application asks whether the owner wants to take part in exchange for a floor area bonus tied to a 30-year commitment. Ask Planning for the current terms.

Zoning, ADUs and selling your home

A legal ADU can raise a home’s appeal. An unpermitted unit is harder to sell: appraisers may not count it, lenders may balk and the seller must disclose it.

The main options are to legalize it using the city’s amnesty policy, to remove or convert it, or to sell as-is.

The council policy says that once a building permit is issued under the amnesty program, the applicant has five years to bring the ADU into compliance with building code standards. Owners who want certainty and speed often choose to sell as-is. See the Del Mar code enforcement guide for how notices work.

How to sell a house in Del Mar with an ADU question

1. Confirm what you have. Check permits for the unit and when it was built.
2. Check the coastal and overlay rules. Ask Planning whether the lot is in a bluff, slope, canyon or beach overlay.
3. Compare costs. Estimate fees and repairs against what the unit adds to the sale price.
4. Decide how to sell. Legalizing may help a retail listing. A cash sale lets you sell as-is.

Related local pages: sell a house as-is in Del Mar, sell my house fast in Del Mar, we buy houses in Del Mar and the Del Mar cash offer process.

Frequently asked questions

How big can an ADU be in Del Mar?

The code accommodates at least 800 square feet and caps interior floor space at 850 square feet, or 1,000 square feet with more than one bedroom. An attached ADU is limited to 50 percent of the primary dwelling’s habitable space, and a junior ADU is no more than 500 square feet.

What setbacks and height limits apply?

A new ADU needs four-foot side and rear setbacks. Detached ADUs are limited to 16 feet, or 18 feet near major transit, and the Bluff, Slope and Canyon Overlay applies a 14-foot limit.

Do I need a coastal permit for an ADU?

Approval generally requires an Administrative Coastal Development Permit unless a specific exemption in the code applies.

Can I rent my ADU short term?

No. In residential zones the code requires rental terms longer than 30 consecutive days.

Does the owner have to live on the property?

The code says that beginning January 1, 2025, the owner must reside in the primary dwelling, the ADU or the JrADU for newly created units.

Can I sell a Del Mar house with an unpermitted ADU?

Yes. You can sell as-is to a cash buyer without legalizing the unit. You must disclose it, and a traditional buyer or lender may require permits or repairs.

More guides

• Del Mar Building Permits Guide
• Del Mar Code Enforcement Guide
• We Buy Houses in Del Mar
• We Buy Houses in San Diego County
• San Diego County Property Tax Guide
• Selling a California Home With Unpermitted Work

Sources

• Del Mar Municipal Code Chapter 30.91, ADU Regulations (June 2025)
• City of Del Mar, Accessory Dwelling Units
• City of Del Mar, ADU Incentive Programs
• City of Del Mar, Council Policy 119: ADU Amnesty Program
• City of Del Mar, Uniform Development Application

This guide is general information from public sources, not legal advice. Confirm current rules with the city.