Vacaville, CA Environmental Rules: Flood Zones (2026)

Vacaville's floodplain management ordinance is codified at VMC Chapter 14.18 (Flood Damage Prevention), with general provisions at Section 14.18.030 and flood-hazard reduction provisions at Section 14.18.050. The ordinance adopts FEMA's Flood Insurance Study for Solano County and accompanying Flood Insurance Rate Maps (FIRMs) by reference. Vacaville's principal flood corridors are Alamo Creek (running diagonally through the city from the western hills to the east), Ulatis Creek (flowing south through downtown and east toward the Yolo Bypass), Horse Creek, and Laguna Creek. Properties along these waterways - including portions of Brown Street, Mason Street, Cernon Street, and the older downtown grid, plus newer east-side neighborhoods near Leisure Town Road - sit in Zone A or AE Special Flood Hazard Areas (1% annual chance flood). Construction in SFHAs requires a Floodplain Development Permit; new structures must elevate the lowest finished floor to at least the Base Flood Elevation (BFE), often with one foot of freeboard, plus flood vents on enclosed areas below BFE. Substantial improvements (cumulative cost >= 50% of pre-improvement market value) trigger full SFHA compliance. Vacaville participates in the National Flood Insurance Program (NFIP), which makes federally backed flood insurance available; properties in SFHAs with federally backed mortgages must carry it. Solano County Water Agency provides a Solano Flood Hazard Information page; FEMA Map Service Center (msc.fema.gov) gives parcel-specific lookups.