The 60% line
There's one line on Solana Beach's FAR worksheet that quietly decides many ADU sizes: the 60% threshold. Per the Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025), if total proposed floor area exceeds it, the ADU is limited to 800 sq ft.
Run it before you sketch
- Find your zone and whether the SROZ applies.
- Calculate maximum floor area with the tiers.
- Add existing house and garage, subtract the garage exemption (up to 400 sq ft) and 800 sq ft of the ADU.
- Compare with the threshold.
If you're over
An 800 sq ft ADU is still a full one-bedroom home, and it lines up with the PADU size limit, which may open a streamlined review. See PADU plans.
The tiers, side by side
| 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).
Questions we hear
- Does the garage count? Yes, minus up to 400 sq ft for two clear 9 by 19 ft spaces.
- Is FAR measured inside? No. Dimensions are to exterior wall surfaces.
- What about an ADU under 800? The full 800 sq ft exemption covers it.
Bottom line
Run the worksheet first. It tells you whether you're designing a 1,000 sq ft unit or an 800 sq ft one.
Fee lines too
At 750 sq ft or less, no impact fees; under 500, no school fees. An 800 sq ft cap sits just above the impact fee line, so a 749 sq ft design can be worth pricing.
Also checked Oct 14, 2026: HCD ADU Handbook (March 2026).
And the bedroom cap
Even below the 60% line, the code caps a studio or one bedroom at 850 sq ft; 1,000 needs two bedrooms.
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.