Junior ADUs (JrADUs) in Del Mar
Del Mar calls them JrADUs. They're the lightest-touch way to add a home: a suite inside the house or attached garage, up to 500 sq ft (Del Mar Municipal Code Chapter 30.91 (June 2025)).
JrADU rules
| Standard | Del Mar rule |
|---|---|
| Zones | R1-40, R1-14, R1-10, R1-10B, R1-5, R1-5B, and CVPP residential lots 3-9, 11-17, 20-29 |
| Size | 500 sq ft maximum |
| Location | Entirely within the walls of the house; an attached garage counts |
| Number | One per lot; not in multiple dwelling lots or detached structures |
| Entry | Separate exterior entry; no interior connection required |
| Kitchen | Cooking facility with appliances, prep counter and storage cabinets |
| Bathroom | Within the JrADU or access to the house's |
| Owner | Owner resides in the house or JrADU (except public agency, land trust or nonprofit housing owner) |
| Rental | Longer than 30 consecutive days; no separate sale or condo conversion |
| FAR | FAR can't prohibit a JrADU within the house's walls |
| Sprinklers | Not required if the house has none |
| Connection fees | None for converting existing space with the right meter size |
Source: DMMC §30.91.020, §30.91.050.
Junior ADU vs ADU
| JrADU | ADU | |
|---|---|---|
| Size | 500 sq ft | 850 / 1,000 sq ft (attached: 50% of house) |
| Where | Inside the house | Inside, attached or detached |
| Paired with | A detached ADU | A JrADU only if the ADU is detached |
Step by step
- Confirm your zone allows JrADUs
- Choose the space and exterior entry
- Plan the kitchen and bath access
- Submit site plan and floor plan (geotechnical report if converting non-habitable space in the Coastal Bluff Overlay Zone)
- Record the deed restriction
- Build and inspect
Questions homeowners ask
- What is a JADU vs ADU? In Del Mar a JrADU is up to 500 sq ft inside the house; an ADU can be larger, attached or detached.
- Can I build a JrADU with an attached ADU? No. Only a detached ADU can be paired with a JrADU.
Why a JrADU often makes sense in Del Mar
A JrADU sits entirely within existing walls, so many of Del Mar's coastal and design questions don't arise: the FAR can't prevent it, there's no new footprint near trees or slopes, and conversion of existing habitable space without replacing roofs, walls or foundations is exempt from the coastal permit. It also pairs with a detached ADU, so it can be phase one of a two-unit plan.
Fire and safety
A JrADU isn't treated as a separate dwelling for fire and life safety rules; requirements for the house apply to the whole structure, and special standards that wouldn't apply to the house aren't required. Sprinklers aren't required if the house has none.
Nonconforming houses
If the JrADU work becomes redevelopment of a house nonconforming for geologic setbacks, public views, coastal access or habitat buffers, the city requires correcting those conditions. Redevelopment means replacing 50% or more of major structural components, or a 50% increase in floor area.
Decision checklist
- You'll live on the property
- A bedroom or attached garage can take an exterior entry
- 500 sq ft is enough
- You may add a detached ADU later
Sources, checked Oct 14, 2026: Del Mar Municipal Code Chapter 30.91 (June 2025) · Gov. Code §66333.
Questions
Where are JrADUs allowed in Del Mar?
In the single dwelling unit zones R1-40, R1-14, R1-10, R1-10B, R1-5, R1-5B and CVPP residential lots 3-9, 11-17 and 20-29.
Does a Del Mar JrADU need an interior door to the house?
No. The code says JrADUs aren't required to have an interior connection.