For assessing flood risk in California, not all flood maps are created equal. We compared FEMA’s flood maps to independent modeling, including climate-informed flood risk. This comparison illustrates very different pictures of flood risk, depending on the map used and how those maps were created, with implications for how California manages infrastructure and prepares for future flooding. Since the 1960s, the Federal Emergency Management Agency (FEMA) has been charged with mapping and managing flood risk in the US. FEMA’s Special Flood Hazard Area (SFHA) defines the 100-year floodplain (or 1% annual chance of flood) and is the regulatory basis for floodplain management nationwide, including whether or not flood insurance is required for many US homeowners.