Rialto, CA Environmental Rules: Flood Zones (2026)
FEMA flood zone rules in Rialto, CA, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.
Key Facts
- Governing chapter
- RMC Ch. 18.75, Floodplain Management
- Permit required for
- Any construction/development in flood hazard area
- Administrator
- City Engineer
- Map source
- FEMA San Bernardino County FIS, 5-8-2024
- Violation penalty
- Misdemeanor
Summary
Rialto requires a development permit before any construction or other development begins in an area of special flood hazard, based on FEMA's San Bernardino County Flood Insurance Study. The City Engineer administers the program as floodplain administrator.
A development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in Section 18.75.070. Application for a development permit shall be made on forms furnished by the Floodplain Administrator and may include, but not be limited to: plans in duplicate drawn to scale showing the nature, location, dimensions, and elevation of the area in question; existing or proposed structures, fill, storage of materials, drainage facilities; and the location of the foregoing.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 39).
Full Breakdown
Chapter 18.75, the Floodplain Management Ordinance, applies to all areas of special flood hazard within the city under Section 18.75.060. Section 18.75.070 adopts by reference FEMA's Flood Insurance Study for San Bernardino County and Incorporated Areas (dated May 8, 2024) and its Flood Insurance Rate Maps, on file at the Engineering Division, 150 South Palm Avenue. Section 18.75.130 requires a development permit before any construction or other development begins within a mapped special flood hazard area, on forms from the floodplain administrator. The application must include a dimensioned site plan, spot ground elevations at building corners, proposed water supply and sewer locations, the base flood elevation if available, and the location of any regulatory floodway, plus foundation design detail showing the lowest floor elevation and fill compaction data (compacted to ninety-five percent under the Standard Proctor Test).
Section 18.75.140 designates the City Engineer as floodplain administrator, responsible for granting or denying permits, reviewing federal and state permit compliance, and confirming a site is 'reasonably safe from flooding.' Section 18.75.080 makes noncompliance a misdemeanor and lets the city council take further lawful action to prevent or remedy violations. The chapter also sets standards for floodways (Section 18.75.220), subdivisions, manufactured homes and recreational vehicles sited in mapped flood zones.
Violations & Fines
Constructing, locating, extending, converting or altering a structure in a special flood hazard area without full compliance with Chapter 18.75, including without an approved development permit, is a misdemeanor under Section 18.75.080. The city council may also take other lawful action to prevent or remedy the violation.
Frequently Asked Questions
Do I need a special permit to build in a Rialto flood zone?
Who decides if my Rialto property is in a flood hazard area?
What happens if I build without a flood zone development permit?
Sources & Official References
Other rules in Rialto
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Flood Zones in Nearby Cities
How other cities in San Bernardino County handle flood zones.