Flood Zones: Costa Mesa vs Santa Ana
How do flood zones rules compare between Costa Mesa, CA and Santa Ana, CA?
Costa Mesa and Santa Ana have similar restriction levels.
Costa Mesa, CA
Orange County
Costa Mesa participates in the National Flood Insurance Program (NFIP) and regulates floodplain development under Title 13 (Planning, Zoning and Development), Chapter V, Article 8 of the Costa Mesa Municipal Code. Sections 13-81 through 13-83 govern uses permitted in designated floodway fringe and Special Flood Hazard Areas (SFHAs) shown on FEMA Flood Insurance Rate Maps, development standards for floodway areas, and exceptions. The Santa Ana River forms Costa Mesa's western boundary and Upper Newport Bay borders the city's eastern edge - both are primary regulated drainages. State authority for floodplain regulation derives from California Water Code Sections 9100 et seq. (Flood Control) and Section 8400 (state floodway designation). FEMA's currently effective Orange County FIRM panels apply to all floodplain determinations within city limits.
View full Costa Mesa rules →Santa Ana, CA
Orange County
Santa Ana participates in the National Flood Insurance Program and enforces floodplain development regulations for properties in FEMA-designated Special Flood Hazard Areas. The city's floodplain management ordinance requires structures in flood zones to be elevated above base flood elevation. The Santa Ana River corridor and Santiago Creek present the primary flood risks within city limits.
View full Santa Ana rules →Key Facts Comparison
| Fact | Costa Mesa | Santa Ana |
|---|---|---|
| Local Code | Costa Mesa MC Title 13, Chapter V, Article 8 (Sections 13-81 to 13-83) | - |
| State Law | Cal. Water Code Sections 9100, 9620, 9650 | - |
| Federal Law | 44 CFR Parts 59-72 (NFIP) | - |
| Primary Drainages | Santa Ana River (west), Upper Newport Bay (east) | - |
| Flood Maps | FEMA Orange County FIRM (msc.fema.gov) | - |
| NFIP Status | Participating community | - |
| Permit Authority | Costa Mesa Development Services / Building Division | - |
| Elevation Cert. | Required for new/substantially improved structures in SFHA | - |
| NFIP Participant | - | Yes — National Flood Insurance Program |
| Primary Flood Sources | - | Santa Ana River and Santiago Creek |
| Elevation Required | - | Above Base Flood Elevation in SFHA |
| FEMA Maps | - | Flood Insurance Rate Maps (FIRMs) |
| Permit Required | - | Floodplain development permit for SFHA work |
Highlighted rows indicate differences between cities.
Costa Mesa FAQ
Santa Ana FAQ
How do I find out if my Santa Ana property is in a flood zone?
Check the FEMA Flood Map Service Center or contact the city's Public Works department. The Santa Ana River corridor and Santiago Creek areas are the primary flood risk zones.
What building requirements apply in Santa Ana flood zones?
Structures in Special Flood Hazard Areas must be elevated above Base Flood Elevation and comply with the city's floodplain management ordinance. A floodplain development permit is required.
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