County of Ventura Floodplain Management Ordinance 4521, specifies that property owners who wish to develop in the 1% annual chance floodplain (100-year floodplain) must obtain a Floodplain Development Permit from the Public Works Agency prior to the issuance of a Building Permit or a Grading Permit. A Floodplain Development Permit is required to ensure that development is compliant with the County’s Ordinance and the National Flood Insurance Program (NFIP). 

Regulating development in floodplains is important not only because it helps prevent potential loss of life and property, it ensures that buildings, fill and other materials do not obstruct flood flows and subsequently cause flooding impacts elsewhere outside of the floodplain.

If your home or business is located within a 1% annual chance floodplain (formerly referred to as the 100-year floodplain) and you are planning to build a room addition or make a major structural renovation or other improvements, and you obtained a County Building Permit for your existing building before October 31, 1985, then your construction project may be subject to the 50% Substantial Improvement provisions of the National Flood Insurance Program (NFIP).