ADU design in Del Mar: the objective standards
Del Mar ADUs are exempt from Design Review, but Chapter 30.91 lists objective design standards. They apply unless they'd prevent an 800 sq ft ADU (Del Mar Municipal Code Chapter 30.91 (June 2025)).
| Topic | Standard (DMMC §30.91.040(I)) |
|---|---|
| Wall and roof planes | At least one projection, offset or recess of 1 ft or more every 20 ft |
| Privacy | Offset windows from neighbors; else obscured glass, clerestories or high sills; no glass walls (75%+ glazing) visible from neighbors; tinted skylights |
| Roof decks | Prohibited |
| Fireplaces | Attached, minimum code height, not in setbacks |
| Setbacks | Eaves and overhangs can't encroach into 4 ft side/rear |
| Matching | Within 20 ft of or attached to the house: same style, roof pitch, materials, colors, windows, doors, fixtures, railings |
| Foundation | Fully screened in matching materials |
| Electronics | No outdoor speakers or TVs |
| HVAC | Within setbacks, screened, meets noise rules |
| Equipment and trash | Screened; trash at rear or interior side |
| Retaining walls | 4 ft max, natural materials, earth tones; 4 ft from building walls |
| Driveways | One, 10 to 20 ft wide; 15% grade (20% with broom-finish concrete); no circular driveways |
| Trees | Not within protected tree driplines unless needed for 800 sq ft |
| Lighting | Shielded, 2700K max, downward, Dark Sky certified, with controls |
Source: DMMC §30.91.040(I), (L).
Scenic views
Public scenic views must not be obstructed if a feasible alternative siting exists. There's no protection of private views from or toward an ADU.
Historic properties
In a historic district or on a listed property, the design must be consistent with the Secretary of the Interior's Standards.
Design checklist
- Plane offsets every 20 ft
- Window study against neighbors
- Matching palette if within 20 ft
- Lighting schedule with Dark Sky fixtures
- Equipment screening
- Landscape per the Water Efficiency Landscape Ordinance
Questions homeowners ask
- Is there design review for Del Mar ADUs? No discretionary Design Review; objective standards apply instead. Extra equipment or features beyond what's required can trigger Design Review.
- How much is an architect for an ADU? We don't publish fees; Del Mar's standards add detailing, so we scope it in writing first.
How we design to these standards
We start with a neighbor window study: we map adjacent windows and place ours to avoid direct views, using clerestories and high sills where they can't be offset. Then massing: plane breaks every 20 ft, roof pitch matched where required. Then the details reviewers check: screened equipment, trash at the rear or interior side, Dark Sky fixtures at 2700K or warmer with controls, and earth-tone retaining walls in natural materials.
What triggers Design Review anyway
Any accessory mechanical equipment or exterior feature not required by the chapter or the building code is subject to Design Review under Chapter 23.08. In the Floodplain Overlay Zone, an elevated ADU's entry wider than the building code minimum needs an Administrative Design Review Permit.
Sources, checked Oct 14, 2026: Del Mar Municipal Code Chapter 30.91 (June 2025).
Questions
Do Del Mar ADUs have to match the house?
If attached or within 20 ft of the house, yes: same style, roof pitch, materials, colors and fixtures.
Are roof decks allowed on Del Mar ADUs?
No. Rooftop decks are prohibited, including those reached from a second-story ADU.