Natural hazards · Castle Hill

Castle Hill, CA natural hazards

Most of the natural-hazard damage FEMA expects in Castle Hill comes from inland flooding, and overall the risk is very high for a U.S. community. Flood insurance has paid 53 claims here since 1982.

FEMA National Risk Index, December 2025 · OpenFEMA claims, aid & declarations

Expected damage

How exposed is Castle Hill?

Very high

vs. U.S. communities

FEMA expects yearly storm and flood damage to homes and buildings in Castle Hill to be higher than in 99% of U.S. communities, mostly from inland flooding and earthquakes.

Inland flooding69%Earthquakes30%Everything else1%

By hazard

What Castle Hill faces

Each hazard’s share of the damage FEMA expects here, and how that compares with the rest of the country.

Inland flooding

69% of expected damage

Well above average · among the top 1% of U.S. places

Recorded about once a year in the area

Earthquakes

30% of expected damage

Well above average · higher than 95% of U.S. places

Lower here

TornadoesHailHeat wavesWildfireLandslidesStrong windLightningVolcanic activity

Not a risk here

Coastal floodingHurricanesIce stormsWinter weatherCold wavesDroughtAvalanchesTsunamis

Flood risk changes street by street. Check a specific address on FEMA’s flood map, and ask about flood insurance before you buy.

Flood insurance claims

Does Castle Hill flood?

Every paid claim on a federal flood insurance policy in Castle Hill, from FEMA’s records.

53paid claims since 1982

$1.1Mpaid to owners

0homes flooded more than once

19822026

Biggest named events

California Atmospheric River: 6 claims, $303K
Pineapple Express - Southern: 1 claim, $5K

of homes in flood zones
are insured

of all homes
are insured

No community discount. Castle Hill isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.

Insurance rates: Contra Costa County.

Disasters that hit Castle Hill

Federal disasters declared here

None of the disasters declared for Contra Costa County shows FEMA aid or repair money reaching Castle Hill itself in FEMA’s records.

Brought FEMA money into Castle HillDeclared for Contra Costa County only

Contra Costa County has had 17 natural disasters declared since 1953, most often floods and severe storms.

Around Castle Hill

Castle Hill and the towns around it

Very lowLowModerateHighVery high

Castle Hillmostly inland floodingVery high

Walnut Creekmostly earthquakesVery high

Alamomostly earthquakesVery high

About these numbers

How to read this page

An average, not a forecastFEMA’s National Risk Index estimates the damage 18 kinds of natural hazards cause in a typical year, from decades of records and models. A quiet decade can follow a bad year.

Compared by rate“Higher than N%” compares yearly damage as a share of what’s here, so a big city isn’t rated riskier just for having more buildings. Castle Hill covers 1 census tract, combined by population.

Money that reached townFlood claims are matched to Castle Hill’s own flood-insurance community (here, the census tracts inside it); household aid to the registrant’s city; repair grants to Castle Hill. FEMA’s model follows property values, so a place that recently lost many homes can rate lower than it feels.

FEMA’s expected losses across Castle Hill total about $13.2M a year, counting buildings, people and crops.

Sources: FEMA National Risk Index (December 2025); OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Census tracts: U.S. Census Bureau.