Martinez, CA Environmental Rules: Flood Zones (2026)

Martinez participates in the National Flood Insurance Program (NFIP) and has adopted a Flood Damage Prevention Ordinance under Martinez Municipal Code to comply with FEMA requirements. FEMA Flood Insurance Rate Maps (FIRMs) for Contra Costa County show Special Flood Hazard Areas along the Carquinez Strait/Suisun Bay shoreline (including the Martinez waterfront, Martinez Marina, and the industrial/refinery areas along Waterfront Road and Pacheco Boulevard), along Alhambra Creek through downtown, and along portions of Franklin Canyon Creek and other tributaries. Zone AE indicates a 1% annual chance (100-year) flood with published Base Flood Elevations (BFEs); Zone VE indicates coastal high-hazard areas subject to wave action. In SFHAs, new construction and substantial improvements (improvements valued at 50% or more of the structure's pre-improvement market value) must have the lowest floor elevated to or above the BFE (typically BFE + 1 foot freeboard under Martinez' ordinance). Nonresidential structures may be dry-floodproofed to the BFE. Substantially damaged structures (damage of 50%+ of market value regardless of cause) must be rebuilt in compliance with current floodplain standards, not replicated at existing elevation. Building permit applications in SFHAs require submission of an Elevation Certificate prepared by a licensed surveyor and a floodplain development permit in addition to the standard building permit. Federally regulated mortgage lenders are required to require flood insurance on structures in SFHAs; post-2021 FEMA Risk Rating 2.0 has changed pricing significantly. Fill, grading, and structures in the floodway (the portion of the floodplain that carries active flood flows) are more strictly regulated and generally prohibited if they would cause any increase in BFE. Alhambra Creek has experienced flooding events (notably in 1982, 1986, 1997, 1998, and 2023), and the Contra Costa County Flood Control and Water Conservation District maintains creek facilities.