Riverside, CA Environmental Rules: Flood Zones (2026)

020 lists the methods Riverside uses to reduce flood losses within the areas mapped by FEMA's Flood Insurance Study, including 'restricting or prohibiting uses which are dangerous to health, safety, and property due to water or erosion hazards,' requiring flood-vulnerable uses to be 'protected against flood damage at the time of initial construction,' controlling alteration of floodplains and stream channels, controlling fill and grading that could increase flood damage, and preventing flood barriers that would divert floodwater onto other properties. 030 applies the chapter to 'all areas of special flood hazards' shown on the FEMA Flood Insurance Rate Maps dated August 2, 1996, and later revisions, kept on file at the Public Works Department, 3900 Main Street.

090 requires anyone developing in a special flood hazard area to submit a development permit application showing the location, dimensions, and elevation of the site, proposed water and sewer connections, grading and drainage plans, the location of any regulatory floodway, and base flood elevation data. 045 to confirm the site is 'reasonably safe from flooding,' that cumulative development won't raise the base flood elevation more than one foot anywhere in the City, and that all state and federal permits, including FEMA Letters of Map Revision, are in hand before a building permit issues.