Flood Zones: Castro Valley vs San Leandro
How do flood zones rules compare between Castro Valley, CA and San Leandro, CA?
Castro Valley and San Leandro have similar restriction levels.
Castro Valley, CA
Alameda County
Alameda County participates in NFIP. FEMA maps designate Special Flood Hazard Areas along the Bay shoreline in Oakland, Alameda, San Leandro, Hayward, and creek corridors countywide.
View full Castro Valley rules →San Leandro, CA
Alameda County
San Leandro is a participating community in the National Flood Insurance Program (NFIP). Floodplain management is codified in San Leandro Municipal Code (SLMC) Title 7, Chapter 7-9 (originally adopted by Ordinance 99-07). FEMA's December 21, 2018 Coastal Flood Insurance Rate Map (FIRM) revision identifies Special Flood Hazard Areas (Zone AE and Zone X) along the San Francisco Bay shoreline, the San Leandro Marina, San Lorenzo Creek, and Estudillo Canal.
View full San Leandro rules →Key Facts Comparison
| Fact | Castro Valley | San Leandro |
|---|---|---|
| Program | NFIP and Community Rating System | - |
| Code authority | Alameda County Code Title 13 | - |
| SFHA construction | Elevate to BFE | - |
| Substantial improvement | 50 percent of value | - |
| Key creeks | Alameda Creek, San Lorenzo Creek | - |
| Code Section | - | SLMC Title 7, Chapter 7-9 (Ord. 99-07) |
| FIRM Effective Date | - | December 21, 2018 (Alameda County coastal) |
| High-risk Zones | - | Zone AE along Bay shoreline, Marina, San Lorenzo Creek |
| Elevation Standard | - | Lowest floor at or above Base Flood Elevation |
| Substantial Improvement Trigger | - | 50% of pre-improvement market value |
| Floodplain Administrator | - | Building & Safety Division (510) 577-3420 |
Highlighted rows indicate differences between cities.
Castro Valley FAQ
Is my home in a flood zone?
Check FEMA's Flood Map Service Center at msc.fema.gov by entering your address. Zones A, AE, and VE are Special Flood Hazard Areas where flood insurance is required for federal mortgages.
Can I remodel in a flood zone?
Yes, but if improvements exceed 50 percent of market value (substantial improvement), the entire structure must be brought up to flood-resistant standards including elevating to BFE.
San Leandro FAQ
Is my San Leandro home in a FEMA flood zone?
Use FEMA's Map Service Center (msc.fema.gov) and enter your address to view the effective FIRM panel for Alameda County (December 21, 2018 revision). Most flood risk is concentrated west of I-880, around the Marina, and along San Lorenzo Creek and Estudillo Canal. The City Building & Safety Division at 510-577-3420 can also confirm your zone.
What happens if my San Leandro home is substantially damaged in a flood?
Under SLMC 7-9, if repair costs equal or exceed 50% of the structure's pre-damage market value, the entire building must be brought into full floodplain compliance, including elevating the lowest floor to or above the Base Flood Elevation and obtaining a FEMA Elevation Certificate. This rule also applies to any voluntary remodel exceeding 50% of value.
Does San Leandro require freeboard above the Base Flood Elevation?
San Leandro's adopted floodplain ordinance (SLMC Chapter 7-9, Ord. 99-07) requires elevation to or above the 100-year (BFE) flood elevation. Property owners should consult Building & Safety at 510-577-3420 for current freeboard requirements under any 2022 California Building Code amendments adopted by the City.
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