Detached ADUs in Solana Beach
A cottage in the back garden is the most popular ADU in Solana Beach, and the city's June 2025 submittal handout is unusually specific about how it must be drawn. These are the rules that shape a detached ADU here, taken from the Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025) and SBMC 17.60.210(A).
The site rules
| Separation from house | 6 ft minimum, eave to eave |
|---|---|
| Entrance facing another wall | 10 ft minimum, eave to eave |
| ADU setbacks | 4 ft lines shown on site plan and floor plans |
| Projections | Eaves, awnings, bay windows and balconies up to 2 ft, not into required side or rear yards |
| Entrance | Primary entrance not visible from the street adjacent to the front yard setback |
| Grading | No ADU where more than 50 cubic yards is required to create it |
| Style | New construction uses the same architectural style, exterior materials and colors as the house |
Floor area
Solana Beach uses floor area ratio tiers. The worksheet deducts up to 800 sq ft of the ADU, and if total proposed floor area exceeds the 60% threshold, the ADU is capped at 800 sq ft. See floor area and the 800 sq ft rule.
Height
State law requires cities to allow at least 16 ft for a detached ADU on a single-family lot, more in some transit-adjacent cases (Gov. Code §66321). The PADU program uses a 16 ft maximum measured from the lower of pre-existing or proposed grade.
Utilities and solar
- A new-construction ADU must have a new or separate utility connection; a sub-meter may be allowed
- Sewer from the ADU connects to the house's sewer on private property; one lateral per APN
- A newly built, non-manufactured detached ADU generally needs solar under the Energy Code, on the ADU or the house
Shortcut
If you want a detached ADU of 800 sq ft or less, a city pre-approved plan may simplify review. See PADU plans.
Detached vs attached in Solana Beach
| Topic | Detached | Attached |
|---|---|---|
| Separation | 6 ft eave to eave from the house; 10 ft if the ADU entry faces another wall | Not applicable |
| Interior access to the house | Not applicable | Not allowed |
| Solar (Energy Code) | Required for new, non-manufactured detached ADUs, with exceptions | Not required for additions |
| Utility connection | New or separate connection required for new construction; a sub-meter may satisfy it | Same rule for new construction |
| Style | Same style, materials and colors as the house | Same |
Source: Solana Beach ADU handout (June 2025).
The floor area math
Size here starts on the FAR worksheet. Maximum floor area depends on zone:
| Lot type | Maximum floor area tiers |
|---|---|
| HR and MHR zones | Lot area x 0.75 |
| Scaled Residential Overlay Zone (SROZ) | 0.500 of first 6,000 sq ft + 0.175 of 6,001 to 15,000 + 0.100 of 15,001 to 20,000 + 0.050 above 20,000 |
| Other residential | 0.600 of first 5,000 sq ft + 0.300 of 5,001 to 20,000 + 0.150 above 20,000 |
Source: Solana Beach ADU handout (June 2025).
On the worksheet you add the existing house, garage and proposed ADU, then deduct the garage exemption (200 sq ft per qualifying 9 by 19 ft space, up to 400) and 800 sq ft of the ADU. If the total exceeds the 60% Design Review threshold, the ADU is limited to 800 sq ft. See floor area and 800 sq ft.
Permit walkthrough
- Get the Coastal Commission approval letter; the city asks for it with the application.
- Email the building permit application, a PDF plan set and the coastal letter to counter@cosb.org.
- The Building Permit Technician invoices plan check and address assignment fees, based on scope, size and valuation.
- After payment, plans route electronically to Planning, Building, Engineering and Fire, plus the third-party landscape reviewer if a landscape package is required.
- Planning assigns the ADU's new address during first review; it then goes on the plans.
Decision checklist
- Grading for the ADU stays at or under 50 cubic yards
- There's room for 6 ft separation (10 ft if the door faces a wall)
- Primary entrance isn't visible from the street beside the front yard setback
- Eaves and decks stay out of side and rear setbacks
- Sewer can join the house lateral on private property
- New landscape area stays under 500 sq ft, or you're ready for a landscape package
Also checked Oct 14, 2026: Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025).
Solana Beach moved its ADU rules to SBMC 17.60.210(A) through Ordinance 542 (2026), which repealed former 17.20.040(D). The June 2025 handout still cites the old section; the standards below follow the current code.
Size and height
Per SBMC 17.60.210(A): 850 sq ft (studio or one bedroom) or 1,000 sq ft (two or more bedrooms); 16 ft, or 18 ft within half a mile walking distance of a major transit stop or high-quality transit corridor, plus 2 ft for a roof pitch matching the house. Occupancy waits until the city approves occupancy of the primary dwelling when built with a new house.
Also checked Oct 14, 2026: SBMC §17.60.210(A) (Ord. 542, 2026).
Sources, checked Oct 14, 2026: Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025) · Solana Beach PADU Processing Guide · Gov. Code §66321.
FAQ
How far must a detached ADU be from the house?
At least 6 ft eave to eave, and 10 ft if the ADU entrance faces the wall of another structure on the property.
Does a detached ADU count toward floor area?
Up to 800 sq ft of the ADU is deducted through the ADU FAR exemption. If total floor area exceeds the 60% threshold shown on the city's worksheet, the ADU is limited to 800 sq ft.
Does the ADU need its own address?
Yes. Planning assigns a new address during first review, and it must appear on the plans.
How far must a detached ADU be from the house in Solana Beach?
At least 6 ft eave to eave, and 10 ft from the ADU entrance if it faces the wall of another structure, per the city handout.
Does a detached ADU need solar in Solana Beach?
Newly constructed, non-manufactured detached ADUs are subject to the Energy Code solar requirement, with exceptions; panels can go on the ADU or the house.