1,202 flood insurance claims·$12.9M paid·10 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Contra Costa County, California. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Contra Costa County experiences a flood risk profile dominated by standard river and surface flooding, with 58 general flood events recorded over the last 30 years compared to 12 flash flood events and 3 coastal flood events.
Recent regional storm impacts include an intense atmospheric river on February 4, 2025, that brought heavy rain and strong winds to the Bay Area, and a series of storm systems spanning December 19 to 25, 2025, which disrupted holiday travel and caused widespread regional flooding.
Property owners and real estate agents should pay the closest attention to locations within Zone A, which accounts for the vast majority of historical claims (620 claims with an average water depth of 8 inches and an average payout of $23,107). Additionally, properties in Zone X require careful review, as this category recorded 174 claims with an average water depth of 9 inches and an average payout of $29,048, alongside smaller claim volumes in shaded and unshaded X zones.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
24% of Contra Costa County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
819 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 6 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 1982, with 141 claims and $478,681 paid.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
30 NOAA storm reports from Contra Costa County describe what happened, in the words of the forecasters who covered it. Read the California flood stories →
21 federal disaster declarations since 1969, 10 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Winter Storms, Flooding, And Mudslides | Jan 8, 2023 |
| Severe Winter Storms, Flooding, Landslides, And Mudslides | Dec 27, 2022 |
| Severe Winter Storms, Flooding, And Mudslides | Feb 1, 2017 |
| Severe Winter Storms, Flooding, And Mudslides | Jan 18, 2017 |
| Severe Storms, Flooding, Mudslides, And Landslides | Dec 17, 2005 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Winter Storms And Flooding | Feb 2, 1998 |
| Severe Storms, Flooding, Mud And Landslides | Dec 28, 1996 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
73 since 1996: 12 flash floods, 58 river or area floods and 3 coastal floods or surges.
| Event | Date | Damage |
|---|---|---|
| Flood | Dec 22, 2025 | — |
| Flood | Nov 13, 2025 | — |
| Flood | Feb 13, 2025 | — |
| Flood | Feb 4, 2025 | — |
| Flood | Dec 29, 2024 | — |
| Flood | Dec 27, 2024 | — |
| Flood | Nov 23, 2024 | $10 |
| Flood | Nov 22, 2024 | $10 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flood · Dec 22, 2025. A series of storm systems impacted the Bay Area and Central Coast from December 19 to 25th, impacting Christmas holiday travel across the region. The most impactful systems arrived on Christmas Eve and Christmas Day. Two tornado warnings were issued for the coastal regions of San Mateo and Santa Cruz counties based off radar indicated rotation. San Francisco International Airport reported delays of at least 300 fl…
Flood · Nov 13, 2025. An rapidly intensifying low pressure system impacted the Bay Area and Central Coast on November 13, with the associated frontal systems and atmospheric river resulting in numerous flooding impacts and strong winds across the region. High Wind Warnings and Wind Advisories were issued throughout the Bay Area and Central Coast, with the High Wind Warnings focused on the immediate coastal areas. Over 3,500 customers l…
Flood · Feb 13, 2025. A winter storm on February 13 caused widespread flooding and strong winds across the Bay Area and Central Coast.
Flood · Feb 4, 2025. An intense atmospheric river impacted the Bay Area from February 3rd to the 4th, bringing heavy rain and strong wind to the region, especially across the North Bay. The Russian River near Guerneville flooded due to the heavy rain.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Contra Costa County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.