Photo: Utilizer · CC BY-SA 3.0On FEMA’s figures, Walnut Creek faces more hazard damage per building than 96% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Walnut Creek gets a D− for hazard risk: higher expected damage per building than 96% of U.S. towns, #623 of 847 in California. Most of that expected damage is river and rain flooding (56%), then earthquakes (44%). Flood insurance has paid 67 claims here since 1979.
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 stands out about Walnut Creek’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Walnut Creek 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 Walnut Creek’s grade
River and rain flooding is 56% of the building damage FEMA expects in Walnut Creek, and Walnut Creek’s rate of river and rain flooding damage is in the top 6% of U.S. census tracts. Earthquakes add 44%, at a rate in the top 4% of U.S. census tracts.
D− #623 of 847 in California; higher expected damage per building than 96% of U.S. towns (21,298).
Walnut Creek’s residents live in 23 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, Walnut Creek has more expected damage per building than 74% of California towns.
In dollars, FEMA expects about $90.7M a year in losses across Walnut Creek: $78.1M to buildings, the rest to people and crops.
Does Walnut Creek flood? Sometimes: 67 flood claims since 1979
Every paid claim on a federal flood insurance policy in Walnut Creek, from FEMA’s records: 1.9 per 1,000 homes, fewer than 62% of the 13,809 U.S. towns with a flood insurance record.
- The California Atmospheric River6 claims · $368K
- The Pineapple Express - Southern3 claims · $31K
Walnut Creek is in FEMA’s Community Rating System (class 8) for its flood-proofing work.
Insurance rates: Contra Costa County.3 federal disasters brought FEMA money to Walnut Creek
Disasters that paid out in Walnut Creek itself (aid to households or repair grants to the City of Walnut Creek), newest first, with that year’s flood claims.
- 2022Severe Winter Storms, Flooding, Landslides, and Mudslides90 households applied for aid$226K aid approved$976K to the City of Walnut Creek for repairs5 flood claims paid that year
- 2017Severe Winter Storms, Flooding, and Mudslides$97K to the City of Walnut Creek for repairs1 flood claim paid that year
- 2005Severe Storms, Flooding, Mudslides, and Landslides29 households applied for aid$67K aid approved$19K to the City of Walnut Creek for repairs4 flood claims paid that year
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 Walnut Creek after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Walnut Creek archive →Walnut Creek and its neighbors
Walnut Creek is 4th of the 10 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Reliez Valley | Dmore damage than 90% | river and rain flooding | — |
| Acalanes Ridge | Dmore damage than 93% | river and rain flooding | — |
| Pleasant Hill | D−more damage than 95% | river and rain flooding | 34 |
| Walnut Creek | D−more damage than 96% | river and rain flooding | 67 |
| Alamo | D−more damage than 96% | river and rain flooding | — |
| Concord | D−more damage than 96% | river and rain flooding | 29 |
| Lafayette | D−more damage than 98% | river and rain flooding | 19 |
| Contra Costa Centre | D−among the highest damage | river and rain flooding | — |
| Castle Hill | D−among the highest damage | river and rain flooding | 53 |
| Saranap | D−among the highest damage | river and rain flooding | 4 |
| North Gate | — | 806 residents; we grade 1,000+ | |
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 Walnut Creek 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.
- Walnut Creek residents get 10% off flood insurance.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Walnut Creek
Is Walnut Creek at risk for natural disasters?
On FEMA’s National Risk Index, Walnut Creek has higher expected damage per building than 96% of U.S. towns: D− for hazard risk, #623 of 847 in California. Most of the expected damage is river and rain flooding (56%) and earthquakes (44%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Walnut Creek flood?
Flood insurance has paid 67 claims in Walnut Creek since 1979, $1.2M in all, or 1.9 per 1,000 homes, fewer than 62% of U.S. towns with a flood insurance record. 3 properties have flooded more than once. The most claims came from California Atmospheric River (6).
Is Walnut Creek 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 Walnut Creek?
Walnut Creek is in FEMA’s Community Rating System (class 8), which takes 10% off federal flood insurance policies for its flood-proofing work. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Walnut Creek?
By FEMA money that reached Walnut Creek, Severe Winter Storms, Flooding, Landslides, and Mudslides (2022): 90 households applied for aid, $226K approved, and $976K to the City of Walnut Creek for repairs. By flood claims, California Atmospheric River: 6 paid, $368K.
Is Walnut Creek at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (56%), and Walnut Creek’s rate for it is in the top 6% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Walnut Creek.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Walnut Creek’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.