What you can build

Del Mar ADU Regulations & Zoning


Size and Separation

Maximum size 1,000 square feet

Side/rear setbacks 4 feet

Two story No

Building separation 6 feet

Additional Requirements

Soils Report No

Building Verification Survey Yes

Coastal permit (in some areas) Yes

Stormwater Mitigation Yes

Number of ADUs Allowed

How many ADUs can you build in Del Mar?

On Del Mar single-family residential lots, you may build one ADU (either attached or detached) and one Junior ADU (JADUs have an owner occupancy requirement and must be converted from existing space within the primary residence).

How many ADUs does Del Mar allow for multifamily properties?

Del Mar allows up to 2 detached ADUs for multifamily lots with an existing multi-family building. (Meaning: In order to build 2 ADUs, the property must already have at least a duplex on it, not just a single family dwelling)

Non‐livable space within existing multi‐family structures may be converted into an ADU. Examples of areas that can be converted include storage rooms and garage spaces. The maximum number of ADU allowed in a multi‐family structure is equal to 25% of the number of existing multi‐family units in the structure. Fractional units are rounded down. A minimum of one conversion ADU is allowed.

ADU Size & Building Constraints

What size detached ADU can you build in Del Mar?

Del Mar allows for a detached ADU up to 850 sqft for units with 1 bedroom, and up to 1000 sqft for 2+ bedrooms. ADUs up to 800 square feet are exempt from lot coverage requirements. (Meaning: You can build an ADU of this size even if you’re maxed out on lot coverages).

What is the height requirement for an ADU in Del Mar? Can you build a 2-story ADU in Del Mar?

The height of a detached ADU can be up to 16′, though an ADU proposed within the Bluff, Slope, and Canyon Overlay Zone shall be 14′ height maximum.

On a lot that is within one-half mile walking distance of a major transit stop or a high-quality transit corridor, as defined in Section 21155 of the Public Resources Code, the
maximum building height of a detached ADU, shall not exceed 18 feet above grade. An additional 2 feet can be added if the ADU’s roof pitch matches the primary dwelling.

The maximum building height for an attached ADU shall not exceed 25 feet above grade, two stories, or the base zoning requirements; whichever is lower. This shall only apply where an ADU is attached to a primary dwelling unit.

So yes, you could build a two story ADU in some situations. Read more about two story ADUs and height limits.

Does Del Mar allow roof decks on ADUs?

No, roof decks are not permitted on detached ADUs in Del Mar.

How big can an attached ADU be in Del Mar?

The square footage of the ADU shall not exceed 850 square feet in size, or 1,000 square feet maximum if the ADU has more than one bedroom. A proposed, attached ADU shall also be subject to an additional limit of a maximum size of 50 percent of the habitable space of the primary dwelling unit.

What are the requirements of the exterior of the ADU?

The ADU shall comply with the following objective design standards, unless
the design standards prohibit construction of an 800 sq. ft. ADU, notwithstanding Section 30.91.040(G)(5):

  1. Wall and roof planes on each elevation must be varied with at least one projection, offset, or recess of the building (of at least one foot in depth) for each 20 feet.
  2. Walls and windows shall be located so that sight lines maximize privacy and avoid direct views into neighboring homes. Glass walls (any wall plane consisting of more than 75 percent opaque or transparent glazed surface) that are visible from adjacent neighboring homes shall be prohibited. Sizing and placement of windows shall be offset to stagger the window placement in relation to the adjacent neighbor’s windows; or shall utilize obscured or opaque window glass, clerestory windows, or windows with higher sills. Installation of skylights shall be tinted to avoid interior light transmission.
  3. Rooftop decks are prohibited.
  4. Where provided, fireplaces and chimneys shall be attached to the ADU and shall be no higher than the minimum height required per the California Building Code.
  5. ADU roof eaves shall not encroach into four (4) foot side or rear setback.
  6. New detached or attached accessory dwelling units shall be constructed using the same architectural style, roof pitch, exterior building materials, colors and finishes as the primary unit if the accessory dwelling unit is attached to or located within twenty (20) feet of the primary dwelling unit.


What is the setback requirement for an ADU in Del Mar?

ADUs must have 4′ minimum setbacks from rear and side-yard property lines, with front yard setback per zoning standards. An ADU taking advantage of the 4′ setbacks cannot exceed a height of 16 feet. An ADU exceeding 16′ must comply with the setbacks of the underlying zoning. In all cases, ADU shall comply with the required coastal bluff setback in the Coastal Bluff Overlay Zone and the required Beach reservation

Initiative setback in the Beach Overlay Zone. Properties located between ocean and the 1st public roadway shall comply with the street yard setback of the applicable zone where necessary to protect public scenic views to the ocean.

What is the minimum distance the ADU must be from existing structures?

A minimum of six feet between buildings shall be maintained between a detached accessory dwelling unit and all other buildings and structures on the lot.

Additional Requirements

Does Del Mar require in-person submission of plans for an ADU?

No, Del Mar allows digital submission of applications for an ADU.

Does Del Mar require a building verification survey for an ADU?

Yes, Del Mar requires a certification of height, setback, and square footage compliance shall be submitted prior to framing inspection.

Does Del Mar require coastal development permits?

California Gov. Code § 65852.2 provides that the ADU statutes do not supersede or in any way alter or lessen the effect or application of the California Coastal Act, except that the City shall not be required to hold public hearings for Coastal Development Permit applications for ADUs.

The following are exempt from a Coastal Development Permit, except where a permit is otherwise required pursuant to Section 30.91.030(C)(5)(c):

i. The ADU contained entirely within or attached to an existing single dwelling unit.
ii. Minor changes to an existing residential structure that will not involve the removal or replacement of major structural components (e.g. roofs, exterior walls, or foundations) and will have no potential to adversely impact coastal resources pursuant to the certified LCP.

Read more about ADUs in the coastal zone.

Does Del Mar require a soils report for an ADU?

No, Del Mar does not mandate soils reports for ADUs, except in the Coastal Bluff Overlay Zone.

Does Del Mar require storm water mitigation?

Yes, Del Mar requires site drainage and storm water mitigation for ADUs. Finish grading work to create a bio-swale, drainage basin or other contouring work to handle on-site storm water will cost around $5-10K in most cases. Read more about stormwater mitigation for ADUs.


How many ADUs does Del Mar allow for multifamily properties?

Up to two detached accessory dwelling units shall be permitted on a lot with an existing multifamily dwelling, not to exceed 16′ in height.

Can you stack detached ADUs on top of each other?

No, you cannot stack ADUs on top of each other in Del Mar.

Can you attach two ADUs to each other in Del Mar?

Yes, you can attach two ADUs to each other in Del Mar.

Can you convert existing space to an ADU?

Yes, existing non-livable space may be converted to ADUs (e.g. storage areas and garages). The minimum number of ADU conversions allowed is one, up to a maximum equal to 25% of the number of existing multifamily units. This is in addition to the allowed number of detached ADUs.


What is the parking requirement for an ADU in Del Mar?

A parking space is not required for an ADU in any of the following instances:

o Within a one-half mile walking distance from public transit, which includes bus stops.
o Within an established historic district.
o Converted from the existing space of a primary residence or accessory structure, or are attached to an existing or proposed primary residence.

Where can a parking space be located?

If a parking space is required, it may be located within the setbacks and in an existing driveway as tandem parking. Parking spaces don’t need to be replaced when a garage, carport, or covered parking structure is demolished in conjunction with the construction of an ADU or converted to an ADU.

Watch our ADU 101 Webinar

Thinking about building an ADU in San Diego and want to learn more about the whole process? We’d love to help make sure you know exactly how it all works in our on-demand webinar led by SnapADU co-founder, Whitney Hill. Hear the top tips from the top ADU company in San Diego.