John Marsh House · Photo: Robin Mayoff (RHM Images) · CC BY-SA 3.0FEMA puts Brentwood’s expected hazard damage per building above that of 87% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Brentwood gets a D for hazard risk: higher expected damage per building than 87% of U.S. towns, #254 of 847 in California. Most of that expected damage is river and rain flooding (59%), then earthquakes (39%). Flood insurance has paid 1 claim here since 1982.
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
What Brentwood 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
Earthquakes
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.
What’s behind Brentwood’s grade
River and rain flooding is 59% of the building damage FEMA expects in Brentwood, and Brentwood’s rate of river and rain flooding damage is higher than 82% of U.S. census tracts. Next is earthquakes at 39% (higher than 90% of U.S. census tracts).
D #254 of 847 in California; higher expected damage per building than 87% of U.S. towns (21,298).
Brentwood’s residents live in 13 census tracts; FEMA’s figures are combined by where they live.
The typical California town has higher expected damage than 92% of U.S. towns; within the state, Brentwood has less expected damage per building than 70% of California towns.
In dollars, FEMA expects about $34.8M a year in losses across Brentwood: $30.6M to buildings, the rest to people and crops.
Does Brentwood flood? Rarely: 1 flood claim since 1982
Every paid claim on a federal flood insurance policy in Brentwood, from FEMA’s records: 0.0 per 1,000 homes, fewer than 100% of the 13,809 U.S. towns with a flood insurance record.
Brentwood 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.4 federal disasters brought FEMA money to Brentwood
Disasters that paid out in Brentwood itself (aid to households or repair grants to the City of Brentwood), newest first, with that year’s flood claims.
- 2025Wildfires and Straight-line Winds1 households applied for aid$942 aid approved
- 2022Severe Winter Storms, Flooding, Landslides, and Mudslides47 households applied for aid$155K aid approved
- 2020Wildfires1 households applied for aid$7K aid approved
- 2005Severe Storms, Flooding, Mudslides, and Landslides1 households applied for aid$16K aid approved$103K to the City of Brentwood for repairs
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.
Old photos of Brentwood after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Brentwood archive →Brentwood and its neighbors
Brentwood is 2nd of the 3 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
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.
Get ready for what Brentwood faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Brentwood
Is Brentwood at risk for natural disasters?
On FEMA’s National Risk Index, Brentwood has higher expected damage per building than 87% of U.S. towns: D for hazard risk, #254 of 847 in California. Most of the expected damage is river and rain flooding (59%) and earthquakes (39%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Brentwood flood?
Flood insurance has paid 1 claim in Brentwood since 1982, $783 in all, or 0.0 per 1,000 homes, fewer than 100% of U.S. towns with a flood insurance record.
Is Brentwood 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 Brentwood?
FEMA’s Community Rating System list shows no discount for Brentwood’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 Brentwood?
By FEMA money that reached Brentwood, Severe Winter Storms, Flooding, Landslides, and Mudslides (2022): 47 households applied for aid, $155K approved.
Is Brentwood at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (59%), and Brentwood’s rate for it is higher than 82% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Brentwood.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Brentwood’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.