Guest, Sign inJoin

Post to Castle Hill

We’ll email a one-tap link to publish your post. No password, and nothing is public until you click it.
Already a member? Sign in
D−Hazard risk
Natural hazards in Castle Hill · FEMA

On FEMA’s figures, few U.S. towns expect more hazard damage per building than Castle Hill, mostly from river and rain flooding

On FEMA’s National Risk Index, Castle Hill gets a D− for hazard risk: among the highest expected damage per building of U.S. towns. Most of that expected damage is river and rain flooding (74%), then earthquakes (25%). Flood insurance has paid 53 claims here since 1982.

River and rain flooding 74%Earthquakes 25%

Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded

among the highestof U.S. townsLess damageMoreExpected yearly damage per dollar of building, vs. the 21,298 U.S. towns we grade
Hazard risk
D−
in California · among the highest of U.S. towns
Main hazard
River and rain flooding
74% of expected building damage
Flood claims
53
paid since 1982 · $1.1M
Flood claims per home
150 per 1,000
more than 98% of U.S. towns
By hazard

What Castle Hill faces

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

River and rain flooding

74%of expected building damage
Well above average · in the top 1% of U.S. census tracts
Recorded about once a year in the area

Earthquakes

25%of expected building damage
Well above average · in the top 5% of U.S. census tracts
Smaller shares here
 Tornadoes Landslides top 2% Hail Strong wind Wildfire Heat waves Lightning Volcanic activity
FEMA models no building damage here
Coastal floodingHurricanesWinter stormsIce stormsCold wavesAvalanchesTsunamis

Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.

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

What’s behind Castle Hill’s grade

River and rain flooding is 74% of the building damage FEMA expects in Castle Hill, and Castle Hill’s rate of river and rain flooding damage is in the top 1% of U.S. census tracts. Earthquakes add 25%, at a rate in the top 5% of U.S. census tracts.

Where Castle Hill sits
Castle Hill
Least damageMiddleMost damage

D− among the highest expected damage per building of U.S. towns (21,298).

All of Castle Hill’s residents live in one census tract; the figures are that tract’s.

What drives the damage to buildings
River and rain flooding74%Earthquakes25%

In dollars, FEMA expects about $2.3M a year in losses across Castle Hill: $2.2M to buildings, the rest to people and crops.

Shared tract.All of Castle Hill’s 1,271 residents (2020 census) live in one census tract. FEMA publishes its model by tract, so the rate and the hazard mix are the tract’s. The flood claims below are the town’s own.
A shared figure. The grade describes the whole tract, not each street in it, and FEMA’s model is an average year for today’s buildings, not a record: the claims below are the record.

How TownRatings grades hazard risk →

Flood insurance claims

Does Castle Hill flood? Sometimes: 53 flood claims since 1982

Every paid claim on a federal flood insurance policy in Castle Hill, from FEMA’s records: 150.1 per 1,000 homes, more than 98% of the 13,809 U.S. towns with a flood insurance record.

Paid flood claims, by year
1982: 4 claims1983: 1 claim1984: 0 claims1985: 0 claims1986: 2 claims1987: 0 claims1988: 0 claims1989: 0 claims1990: 0 claims1991: 0 claims1992: 0 claims1993: 0 claims1994: 0 claims1995: 0 claims1996: 2 claims1997: 7 claims1998: 1 claim1999: 0 claims2000: 0 claims2001: 0 claims2002: 24 claims2003: 0 claims2004: 0 claims2005: 6 claims2006: 0 claims2007: 0 claims2008: 0 claims2009: 0 claims2010: 0 claims2011: 0 claims2012: 0 claims2013: 0 claims2014: 0 claims2015: 0 claims2016: 0 claims2017: 0 claims2018: 0 claims2019: 0 claims2020: 0 claims2021: 0 claims2022: 6 claims2023: 0 claims2024: 0 claims2025: 0 claims2026: 0 claims199720022005
19822026
Biggest named events
  • The California Atmospheric River6 claims · $303K
  • The Pineapple Express - Southern1 claim · $5K
53
paid claims since 1982
$1.1M
paid to owners
0
homes flooded more than once
$21K
average claim
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

The storms Castle Hill remembers

None of the 17 disasters declared for Contra Costa County shows FEMA aid or repair money reaching Castle Hill itself in FEMA’s records, so these are its biggest flood-claim years.

  1. 200224 flood claims paidNo declaration for the county that year
  2. 19977 flood claims paidNo declaration for the county that year
  3. 20056 flood claims paidThe year of Severe Storms, Flooding, Mudslides, and Landslides, declared for Contra Costa County
Disasters declared, by decade
Paid out in Castle HillContra Costa County only

Contra Costa County has had 17 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.

Were you here?

Old photos of Castle Hill after a storm or flood belong in the town’s history. Add one, or share what you remember below.

Add to the Castle Hill archive →
Next door

Castle Hill and its neighbors

Castle Hill is 3rd of the 3 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.

Alamo: hazard risk D−Walnut Creek: hazard risk D−AlamoWalnut CreekCastle Hill
Lowest fifthSecondMiddleFourthHighest fifth
TownHazard riskMostly (buildings)Flood claims
Walnut CreekD−more damage than 96%river and rain flooding67
AlamoD−more damage than 96%river and rain flooding—
Castle HillD−among the highest damageriver and rain flooding53

Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.

Be ready

Get ready for what Castle Hill faces

A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.

When the river rises
  • Turn around at flooded roads: a foot of moving water can carry off a car.
  • Flood insurance usually takes 30 days to start, so buy it before the forecast.
  • Keep papers and medicines up high, in a grab-and-go bag.
More from Ready.gov ↗
Earthquakes
  • Drop, cover and hold on.
  • Strap tall furniture and the water heater to the wall.
  • Know how to shut off the gas.
More from Ready.gov ↗
Before you buy or rent
  • Look up the address on FEMA’s flood map.
  • Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
  • Get a flood insurance quote early: policies usually start 30 days after you buy.
When a storm is coming
Forecast and alertsWeather →911, the nearest ERSafety →

Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.

Questions about natural hazards in Castle Hill

Is Castle Hill at risk for natural disasters?

On FEMA’s National Risk Index, Castle Hill has among the highest expected damage per building of U.S. towns: D− for hazard risk. Most of the expected damage is river and rain flooding (74%) and earthquakes (25%). The figures are for the one census tract the town shares with its neighbors. This is FEMA’s model of an average year for today’s buildings, not a forecast.

Does Castle Hill flood?

Flood insurance has paid 53 claims in Castle Hill since 1982, $1.1M in all, or 150.1 per 1,000 homes, more than 98% of U.S. towns with a flood insurance record. The most claims came from California Atmospheric River (6).

Is Castle Hill in a flood zone?

Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In Contra Costa County, 28% of homes in mapped flood zones carry federal flood insurance, and 0.9% of all homes do.

How much is flood insurance in Castle Hill?

FEMA’s Community Rating System list shows no discount for Castle Hill’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.

What was the biggest storm in Castle Hill?

By flood claims, California Atmospheric River: 6 paid, $303K.

Is Castle Hill at risk from river and rain flooding?

It is the largest share of the building damage FEMA expects here (74%), and Castle Hill’s rate for it is in the top 1% of U.S. census tracts.

Storm stories

Memories, warnings and help from neighbors in Castle Hill.

Town Square →
Start the conversation

Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Castle Hill’s residents lived in the 2020 census; 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. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.