Enter any address in Contra Costa County, California to see its FEMA flood zone
Flooding events, including flash floods and coastal floods, have been recorded in Contra Costa County over the past 30 years. For example, a series of storm systems brought impactful flooding to the Bay Area around Christmas 2025, disrupting travel. Earlier that year, in November 2025, a rapidly intensifying low-pressure system caused numerous flooding impacts across the region.
National Flood Insurance Program (NFIP) data shows that properties in Zone A have experienced the highest number of claims, with an average payout of $14,464 and an average water depth of 2.4 feet. Properties in Zone X also saw significant claims, with an average payout of $17,257 and an average water depth of 2.6 feet, despite being designated as having a lower flood risk.
Residents in areas designated as Zone A, as well as those in coastal areas or near rivers, should pay particular attention to flood risk. Homeowners in areas designated Zone X, which includes X_UNSHADED and X_SHADED, should also be aware of potential flood impacts, as claims data indicates significant payouts and water depths in these zones as well.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
30 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Contra Costa County, California has recorded 73 flood-related events since 1996 according to NOAA's Storm Events Database, including 12 flash floods and 58 river or area floods. The county has received 21 federal disaster declarations, 10 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1969–2023)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Severe Winter Storms, Flooding, And Mudslides | Flood | Jan 8, 2023 |
| Severe Winter Storms, Flooding, Landslides, And Mudslides | Flood | Dec 27, 2022 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Winter Storms, Flooding, And Mudslides | Flood | Feb 1, 2017 |
| Severe Winter Storms, Flooding, And Mudslides | Severe Storm | Jan 18, 2017 |
| Severe Storms, Flooding, Mudslides, And Landslides | Severe Storm | Dec 17, 2005 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| Severe Winter Storms And Flooding | Severe Storm | Feb 2, 1998 |
| Severe Storms, Flooding, Mud And Landslides | Severe Storm | Dec 28, 1996 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flood | Dec 22, 2025 | 0.00K |
| Flood | Nov 13, 2025 | 0.00K |
| Flood | Feb 13, 2025 | 0.00K |
| Flood | Feb 4, 2025 | 0.00K |
| Flood | Dec 29, 2024 | 0.00K |
| Flood | Dec 27, 2024 | 0.00K |
| Flood | Nov 23, 2024 | 0.01K |
| Flood | Nov 22, 2024 | 0.01K |
| Flood | Jan 20, 2024 | 0.01K |
| Flood | Feb 18, 2024 | 0.00K |
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 delay...
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. Ov...
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.
Flood — Dec 29, 2024
Multiple weather systems moved through California from December 26 to 29, bringing localized flooding and gusty winds to the region.
Source: NOAA National Weather Service Storm Events Database.
Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).
FEMA assigns flood zone designations to areas in Contra Costa County, California:
AE High Risk — 1% annual chance of flooding. Insurance required.
VE Very High Risk — Coastal flooding with wave action.
X (Shaded) Moderate Risk — 500-year floodplain.
X Low Risk — Outside major floodplains.
Properties in Contra Costa County, California that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.
Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.
Visit FloodSmart.gov to find an agent and get a quote.