Enter any address in New Castle County, Delaware to see its FEMA flood zone
Flash flooding from thunderstorms is the most frequent type of flood event in New Castle County, Delaware, with 156 recorded instances over the last 30 years. These events have also resulted in four fatalities. For example, multiple flash flood events occurred on July 31, 2025, triggered by a stationary front that produced showers and thunderstorms. Other flood types, including general floods, coastal floods, storm surge, and tropical storms, have also occurred.
National Flood Insurance Program (NFIP) data shows that properties in Zone A have experienced the highest number of claims, with 874 claims averaging $36,390 and an average water depth of 4.1 feet. While Zone X properties have fewer claims, some, like those in Zone X_SHADED, have seen higher average payouts and water depths than Zone A. Properties in Zone D have had the fewest claims and the lowest average water depth.
Homeowners in flood-prone areas, particularly those in Zone A, and residents near rivers or coastal areas should pay close attention to flood risk. Properties without a Base Flood Elevation (BFE) may also warrant increased awareness due to potential water depths observed in claims data.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
31 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
New Castle County, Delaware has recorded 290 flood-related events since 1996 according to NOAA's Storm Events Database, including 156 flash floods and 96 river or area floods. The county has received 17 federal disaster declarations. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1965–2021)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Remnants Of Hurricane Ida | Hurricane | Sep 1, 2021 |
| Tropical Storm Isaias | Hurricane | Aug 4, 2020 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Hurricane Sandy | Hurricane | Oct 27, 2012 |
| Hurricane Irene | Hurricane | Aug 26, 2011 |
| Severe Winter Storms And Snowstorms | Snowstorm | Feb 5, 2010 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| Severe Storms, Tornadoes, And Flooding From The Remnants Of | Severe Storm | Sep 28, 2004 |
| Hurricane Isabel | Hurricane | Sep 18, 2003 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jul 31, 2025 | 10.00K |
| Flash Flood | Jul 31, 2025 | 0.00K |
| Flash Flood | May 30, 2025 | 0.00K |
| Flash Flood | Jul 9, 2025 | 0.00K |
| Flash Flood | Jul 9, 2025 | 50.00K |
| Flash Flood | Jul 9, 2025 | 20.00K |
| Coastal Flood | Apr 11, 2024 | 0.00K |
| Coastal Flood | Jan 10, 2024 | 0.00K |
| Coastal Flood | Mar 9, 2024 | 0.00K |
| Flood | Jan 9, 2024 | 0.00K |
Flash Flood — Jul 31, 2025
A stationary front sparked off showers and thunderstorms across the forecast area. Flash flooding resulted.
Flash Flood — May 30, 2025
Thunderstorms, in the vicinity a cold front, produced flash flooding.
Flash Flood — Jul 9, 2025
A slow-moving cold front produced heavy rain and flash flooding across portions of the region.
Coastal Flood — Apr 11, 2024
High astronomical tides in addition to strong southerly flow resulted in higher water levels, mainly along the Delaware Bay and tidal Delaware River. However, some flooding was observed in the back bays as southerly flow prevented water from draining.
Coastal Flood — Jan 10, 2024
A strong system affected the region with steady southerly flow pushing water up into coastal communities both along the ocean and within the Delaware River/Bay and Chesapeake Bay. Water levels on the tidal Delaware River were higher due to 2 to 4+ inches of rainfall.
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 New Castle County, Delaware:
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 New Castle County, Delaware 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.