Flood Zones: Altadena vs West Covina
How do flood zones rules compare between Altadena, CA and West Covina, CA?
Altadena and West Covina have similar restriction levels.
Altadena, CA
Los Angeles County
Most of Altadena is in FEMA Flood Zone X (minimal hazard), but the area along Eaton Wash, the Arroyo Seco tributaries, and post-Eaton Fire burn-scar areas have heightened flood and debris-flow risk. LA County Code Ch. 22.142 (Floodplain Management) applies in mapped Special Flood Hazard Areas.
View full Altadena rules →West Covina, CA
Los Angeles County
West Covina participates in the National Flood Insurance Program (NFIP) and regulates development in FEMA-designated flood zones. The City lies in the San Gabriel Valley with waterways including the San Gabriel River and its tributaries. LA County Measure W funds stormwater improvements.
View full West Covina rules →Key Facts Comparison
| Fact | Altadena | West Covina |
|---|---|---|
| Most of Altadena | Zone X (minimal hazard) | - |
| Eaton Wash Adjacent | Zone A / AE possible | - |
| Code Section | LA County Code Ch. 22.142 | - |
| BFE+1 Required | In SFHA | - |
| Post-Eaton Fire | Elevated debris-flow risk | - |
| NFIP Status | - | Participating community |
| Waterways | - | San Gabriel River + tributaries |
| Measure W Tax | - | $0.025/sq ft impervious |
| Flood Maps | - | msc.fema.gov |
Highlighted rows indicate differences between cities.
Altadena FAQ
Is Altadena in a flood zone?
Most of Altadena is in FEMA Zone X (minimal hazard), but areas along Eaton Wash and the foothill channels can be in Zone A/AE. Check the FEMA Map Service Center for your specific parcel.
Did the Eaton Fire affect flood risk?
Yes — post-fire burn scar areas above Altadena have elevated debris-flow and flash-flood risk during winter storms. USGS and NWS issue post-fire debris-flow advisories.
West Covina FAQ
Is West Covina in a flood zone?
Most of the City is outside the 100-year floodplain, but areas near the San Gabriel River and its tributaries (Walnut Creek, San Jose Creek, Big Dalton Wash) may have Zone A or AE designations. Check msc.fema.gov for your property.
What is the Measure W parcel tax?
LA County Measure W (Safe Clean Water Program) charges 2.5 cents per square foot of impermeable area on all parcels within the LA County Flood Control District to fund local water supply and stormwater quality improvements.
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