ADU Builder Del Mar | Size Limits, Coastal Permits, Fees

Short answer

A single-family lot in the City of Del Mar can usually take one ADU plus one junior ADU, but units are capped smaller than in Carlsbad: 850 sq ft, or 1,000 sq ft if it has two or more bedrooms. The whole city sits in the Coastal Zone, so most new units need a staff-level coastal permit. Detached units top out at 16 ft, or 14 ft in the Bluff, Slope and Canyon Overlay. Residential-zone ADUs cannot be short-term rentals. City planning, engineering and coastal fees total about $2,300 before the building permit.

Which "Del Mar" this page covers

Many homes with a Del Mar mailing address are not in the City of Del Mar. Carmel Valley, Del Mar Heights and the streets around Torrey Pines belong to the City of San Diego and follow its ADU rules, which this page does not cover. The City itself runs from the San Dieguito River south to Torrey Pines State Reserve.

How Del Mar differs from Carlsbad

Construction carries over; the rules and fees do not.

Item	City of Del Mar	Carlsbad (for comparison)
Largest ADU	850 sq ft (studio, one-bedroom) or 1,000 sq ft (two-plus bedrooms)	1,200 sq ft detached
Coastal Zone	The entire city	About 37% of the city
Coastal permit	Administrative CDP for most ADUs, including many attached units; exemptions are narrow	Detached units and garage conversions; most attached ADUs and JADUs skip it
Detached height	16 ft; 14 ft in the Bluff, Slope and Canyon Overlay	16 ft, or 18 ft near the Village and Poinsettia stations
Short-term rental	Barred for ADUs in residential zones; citywide cap of 129 STR permits	No rentals of 30 days or less
City fees	$1,192 planning, $748 engineering, $332 coastal permit, plus building permit	About $2,000 to $4,000 for most ADUs

From DMMC Chapter 30.91 (certified by the Coastal Commission June 12, 2025) and the July 2025 fee schedule. Carlsbad details: Carlsbad permit rules page.

Size, height and setbacks

Chapter 30.91 measures size from the inside face of the studs, and all interior floor counts. The City must always allow 800 sq ft; anything past that is checked against the lot's floor area ratio and coverage.

Rule	Detached ADU	Attached ADU	Junior ADU
Maximum size	850 sq ft, or 1,000 sq ft with more than one bedroom	Same caps, and no more than 50% of the home's habitable space (800 sq ft is always allowed)	500 sq ft, inside the home's walls or attached garage
Height	16 ft above grade; 14 ft in the Bluff, Slope and Canyon Overlay	16 ft for one story; a second story to 25 ft or the zone limit, whichever is lower, only if the ground floor cannot fit it	Inside the existing house
Side and rear setback	4 ft, and eaves may not project into it	4 ft	Existing walls

From DMMC 30.91.040 and 30.91.050. Street setbacks follow the zone; buildings need 6 ft of separation.

Pick carefully: an attached ADU rules out a junior ADU on the same lot, while a detached ADU can pair with a junior unit inside the house. Junior ADUs are allowed only in R1 zones. No ADU may sit within the dripline of a Torrey pine or Monterey cypress. On slopes of 25% or more with 20 ft of rise, stay 20 ft from the top and 10 ft from the toe, with grading capped at 200 cubic yards. Our detached ADU page has layouts, though its size and height figures are Carlsbad's.

Coastal permits and design review

Del Mar's certified Land Use Plan states that the entire city is inside the state Coastal Zone. Under DMMC 30.91.030(E), an ADU needs an Administrative Coastal Development Permit unless it only converts existing habitable space or fits the Coastal Commission's narrow Section 13250 exemption. Attached additions get one too: in spring 2026 the City approved permits for an 800 sq ft attached ADU on Van Dyke Avenue and a 738 sq ft attached unit on Crest Road.

Notice
A notice is posted on site and mailed to owners within 300 ft and occupants within 100 ft. No hearing.
Director's finding
The Planning Director finds the unit consistent with the Local Coastal Program.
No appeal
Recent City notices, citing AB 462, say these permits cannot be appealed to the Coastal Commission.

Hands marking up construction drawings with a pencil — Architectural blueprints on a desk. In Del Mar the coastal permit and the building plans are reviewed side by side. Illustrative stock photo (Pexels) — not a project by our contractor.

The Design Review Board, which hears most Del Mar house projects, does not review an ADU built to code; Chapter 30.91 exempts ADUs in every zone. Optional exterior extras can still be reviewed.

Hazards add work. Bluff lots, all in the North Bluff District, keep 40 ft from the edge. Near the San Dieguito River and the fairgrounds, much of the land is 100-year floodplain, so the lowest floor goes one foot above base flood elevation, with elevation certificates. CAL FIRE's 2025 maps, adopted June 16, 2025, expanded High and Very High zones next to open space; check your parcel on the City's map viewer.

Short-term rentals and owner occupancy

After years of argument, Ordinance 1010 (September 2024) was certified by the Coastal Commission 7 to 2 on February 5, 2026: a three-night minimum, a cap of 129 STR permits, a primary-residence rule for new STRs and one STR per lot, ADU included. By May 2026, 99 of 150 existing operators had applied, leaving about 30 slots and a waitlist. For ADU owners it is simpler: rentals must exceed 30 consecutive days, and residential-zone ADUs cannot be STRs. Budget the unit as a long-term rental or family space.

Owner occupancy needs a check. Del Mar's code text says that from January 1, 2025 the owner must live on a lot with a new ADU, but state law (AB 976, 2023) bars cities from requiring that for ADUs. Ask Planning in writing. For a junior ADU the owner lives in the house or the JADU.

Fees, utilities and incentives

Del Mar's July 1, 2025 schedule lists $1,192 for the planning ADU fee, $748 for engineering review and inspection ($518 per extra cycle) and $332 for a staff-level coastal permit. Building permit fees come on top; we found no published ADU figure, so ask the Building Division.

School fees: none at 500 sq ft or less. Above that, San Dieguito Union High lists $2.83 per sq ft of livable space, and Del Mar Union collects its own share by separate check. The state cap on the combined fee rose to $5.38 per sq ft in January 2026.
Water and sewer: the City runs both and buys treated water from San Diego. Conversions with an adequate meter pay no new connection fee; a new building may pay one scaled to size and fixtures, amount unpublished. Bi-monthly base rates on a 5/8 inch meter are $90.47 water and $144.43 sewer.
Impact fees: state law blocks them on ADUs of 750 sq ft or less.

The City's ADU Incentive Program gives owners who deed-restrict a unit for lower-income renters for 30 years a bonus junior ADU and a 500 sq ft floor area bonus for the main house, subject to Design Review Board approval. The earlier pilot produced one such unit in five years. A separate amnesty for unpermitted units (Council Policy 119) was listed through December 4, 2025; we could not confirm an extension.

What a Del Mar ADU costs

Our ADU cost calculator is calibrated to Carlsbad, and Del Mar builds fall in similar coastal North County ranges. Mid finish, standard site: about $330,000 for 750 sq ft detached ($284,000 to $376,000), about $400,000 at 1,000 sq ft, and about $213,000 for a 550 sq ft attached ADU. A 400 sq ft garage conversion runs roughly $145,000 to $153,000 and a 300 sq ft junior unit about $100,000. There is no 1,200 sq ft option here.

Swap in Del Mar's fees, and add a soils report on bluff or canyon lots, flood elevation work near the river and Chapter 7A materials in a mapped fire zone. For compact layouts on tight beach lots, see the attached ADU and JADU page.

Permits and timeline

The City says a complete application that meets Chapter 30.91 is approved within 60 days. A deed restriction is recorded before the building permit issues, and the permit lapses after two years without a certificate of occupancy. Real timing varies: an attached unit on 21st Street carrying a 2024 file number was approved in March 2026. The stages are on our design-build process page.

Rental math

Del Mar has few rentals. Zumper's October 2026 figures: studio $3,167, one-bedroom $3,052, two-bedroom $4,695. Zillow's November 2026 averages are skewed by luxury listings up to $120,000 a month. HUD's FY2026 San Diego metro Fair Market Rents are $2,288, $2,459 and $3,001. Plan on about $2,300 to $3,150 for a studio, $2,500 to $3,050 for a one-bedroom and $3,000 to $4,700 for a two-bedroom.

Worked example: a 750 sq ft one-bedroom at $3,000 a month grosses $36,000. Subtract $1,800 vacancy, $1,800 upkeep and roughly $1,240 of added property tax, and about $31,160 remains before insurance. On a $330,000 build that is near 9.4% a year before financing.

In pictures

Inside a small Del Mar unit

Architectural floor plan drawing on paper — A printed house floor plan

Narrow white kitchen with a large window and built-in appliances — A narrow white galley kitchen

Bedroom with white bedding, wood furniture and bedside lamps — A small bedroom with warm lighting

These are licensed stock photos (Pexels) chosen to show the kind of space or place described. They are not photographs of our contractor's completed projects.

Del Mar ADU questions

My address says Del Mar 92014. Do these rules apply to me?

Only if your lot is inside the City of Del Mar. Carmel Valley, Del Mar Heights and nearby Torrey Pines streets are in the City of San Diego and use San Diego's ADU code. Your property tax bill or the City's map viewer will tell you.

Can I build a 1,200 sq ft ADU in Del Mar?

No. The cap is 850 sq ft, rising to 1,000 sq ft with two or more bedrooms. An attached unit is also held to half the home's habitable space, though 800 sq ft is always allowed.

Can I rent my Del Mar ADU during racing season or on Airbnb?

No. Leases must exceed 30 consecutive days, and the 2024 STR ordinance bans short-term use of residential-zone ADUs.

Is there parking relief near a train station?

Del Mar has no train station; the nearest Coaster stop is in Solana Beach. The half-mile transit waiver may not reach any Del Mar lot, so plan on one space unless another exemption applies, such as converting space inside the house. Ask Planning about your parcel.

Sources

Last checked November 7, 2026. These are the City of Del Mar's rules as published; overlays, flood and fire mapping and fees vary by parcel, so confirm with Del Mar Planning and Community Development before you design.

ADU Builder in Del Mar, CA

Which "Del Mar" this page covers

How Del Mar differs from Carlsbad

Size, height and setbacks

Coastal permits and design review

Notice

Director's finding

No appeal

Short-term rentals and owner occupancy

Fees, utilities and incentives

What a Del Mar ADU costs

Permits and timeline

Rental math

Inside a small Del Mar unit

Del Mar ADU questions

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