1,914 flood insurance claims·$37.5M 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 Chester County, Pennsylvania. 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.
Flash flooding from severe weather events dominates the flood risk profile in Chester County, Pennsylvania. Over the last 30 years, the NOAA Storm Events Database recorded 223 flash flood events resulting in 2 deaths, alongside 70 general flood events resulting in 1 death, and 2 tropical storms. Recent documented activity includes a slow-moving cold front on July 9, 2025, which produced heavy rain and flash flooding across portions of the region over consecutive days.
National Flood Insurance Program records indicate that flood impacts extend across multiple zones, with high-risk Zone A properties bearing the heaviest overall burden with 1,271 claims averaging $25,919 and an average recorded water depth of 8 inches. However, properties outside designated high-risk zones also face significant hazards. Zone X properties recorded 411 claims with an average payout of $28,283 and an average recorded water depth of 17 inches. Zone X shaded properties logged 46 claims with an average payout of $18,175 and an average recorded water depth of 5 inches, while Zone X unshaded properties accounted for 51 claims averaging $15,674 with an average water depth of 4 inches. Properties with unknown zones accounted for 133 claims averaging $2,742 with an average water depth of 3 inches.
Homeowners, real estate agents, and journalists should pay the closest attention to properties located within high-risk Zone A, while remaining aware that moderate-to-low risk Zone X properties have also experienced substantial and costly water accumulation.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
7% of Chester County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
1,369 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 9 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 2021, with 215 claims and $13.7M paid, the year of Remnants Of Hurricane Ida.
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.
42 NOAA storm reports from Chester County describe what happened, in the words of the forecasters who covered it. Read the Pennsylvania flood stories →
26 federal disaster declarations since 1965, 10 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Remnants Of Hurricane Ida | Aug 31, 2021 |
| Severe Winter Storm And Snowstorm | Jan 22, 2016 |
| Severe Winter Storm | Feb 4, 2014 |
| Hurricane Sandy | Oct 26, 2012 |
| Remnants Of Tropical Storm Lee | Sep 3, 2011 |
| Tropical Storm Lee | Sep 3, 2011 |
| Hurricane Irene | Aug 26, 2011 |
| Severe Winter Storms And Snowstorms | Feb 5, 2010 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
295 since 1996: 223 flash floods and 70 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 27, 2025 | — |
| Flash Flood | Jun 27, 2025 | $10,000 |
| Flash Flood | May 16, 2025 | — |
| Flash Flood | May 16, 2025 | $15,000 |
| Flash Flood | May 16, 2025 | $10,000 |
| Flash Flood | May 16, 2025 | $20,000 |
| Flash Flood | Jul 9, 2025 | — |
| Flash Flood | Jul 9, 2025 | $5,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jun 27, 2025. Showers and storms developed behind a backdoor cold front resulting in heavy rain.
Flash Flood · May 16, 2025. Scattered thunderstorms developed along a slow moving warm front.
Flash Flood · Jul 9, 2025. A slow-moving cold front produced heavy rain and flash flooding across portions of the region. This is the same front that caused flash flooding the day prior.
Flash Flood · Jul 8, 2025. A cold front produced heavy rain and flash flooding across portions of the region.
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 Chester 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.