Aging original drainage
Danville's median home was built in 1980 (U.S. Census); Blackhawk's in 1988 and Alamo's in 1978. Many homes have the drainage installed by the original builder: perforated lines without fabric, downspouts tied into French drains, and outlets that landscaping has since buried. When those fail, the symptoms are soggy lawns, water at the foundation and wet retaining walls. Start with French drain repair; if the system is past saving, see installation.
Foothill lots
Homes along the foothills off Diablo Road and in Blackhawk sit below slopes that shed water in long storms. Interceptor drains, swales and piped downspouts keep that water off patios and away from foundations; see hillside drainage.
Town or County permits
| Where you live | Permits through |
|---|---|
| Danville | Town of Danville Permit Center |
| Alamo, Blackhawk, Diablo (unincorporated) | Contra Costa County |
Simple yard drains often need no permit; grading, walls and storm connections can.
HOAs and trees
- Blackhawk HOA requires architectural approval for exterior and landscape changes (Blackhawk HOA).
- Danville protects 12 native species at 10 inches in diameter or more and any tree 36 inches or more (Town of Danville). Plan trench routes around root zones.
Costs and hiring
See the cost guide for Bay Area per-foot ranges and the contractor checklist for what each quote should include.
Danville-area questions
Do I need a permit for drainage work in Danville?
Simple yard drains often don't need one; grading, retaining walls and street or storm connections may. Danville runs its own Permit Center. Alamo, Blackhawk and Diablo are unincorporated, so permits go through Contra Costa County.
Does my Blackhawk HOA need to approve drainage work?
Blackhawk HOA requires architectural approval for exterior and landscape changes (Blackhawk HOA). Get approval before scheduling the work.