San Ramon Valley · Alamo, Blackhawk, Diablo
ADU Builders in Danville, CA
Danville makes detached ADUs easier with its Garden Cottage Program: permit-ready plans you can download free of charge, eligible for expedited processing and lower building permit fees (Town of Danville). The Town also administers the SD7 ADU Accelerator, worth up to $15,000 per qualifying ADU.
Danville programs
Plans and incentives as of October 2026
| Item | Danville | Source |
|---|---|---|
| Pre-approved plans | Garden Cottage Program: detached units only, downloadable at no charge | Town |
| Processing | Pre-plan-checked plans: expedited processing, lower permit and plan-check fees | Town |
| Site fit | Site-specific conditions may need a design professional to confirm the plan works | Town |
| Rebate | SD7 ADU Accelerator up to $15,000; Danville is fiscal agent | SD7 page |
| Sewer | Central San: detached ADU ties into the house lateral downstream of the main cleanout | Central San |
Lots + HOAs
Bigger lots, more HOAs
Many Danville lots have room for a detached unit without crowding the 4 ft setback line, which is exactly what the Garden Cottage plans are built for. A garage conversion stays the budget option for lots without yard space.
HOA neighborhoods. Blackhawk, Diablo and many Danville subdivisions have CC&Rs and design review. California voids HOA rules that prohibit or unreasonably restrict ADUs (Civil Code §4751), but design standards still apply.
Alamo is unincorporated: County rules and PADU vendor plans apply, and it is not on the SD7 list.
FAQ
Danville ADU questions
Does Danville offer free ADU plans?
Can I get the SD7 ADU rebate in Danville?
Can a Blackhawk or Diablo HOA ban ADUs?
Next step
Plan your Danville ADU
Share your lot and goals. A local ADU builder can review feasibility and give you a quote.