3,034 flood insurance claims·$57.1M 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 Delaware 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 heavy rain and severe weather dominates Delaware County, Pennsylvania, accounting for 144 events and one death over the last 30 years out of 273 total flood-related events, which also include standard floods, coastal floods, storm surges or tides, and tropical storms.
Real-world impacts are driven by weather systems such as the slow-moving cold front on July 9, 2025, which produced heavy rain and flash flooding across the region over consecutive days.
National Flood Insurance Program claims data indicates that high-risk Zone A properties face the heaviest financial and physical impacts, with 1,997 claims averaging $27,650 per payout and an average recorded water depth of 11 inches. However, properties in moderate-to-low risk zones also experience significant vulnerabilities; Zone X recorded 667 claims with an average payout of $17,285 and an average water depth of 10 inches, Zone X_SHADED recorded 142 claims with an average payout of $17,310 and an average water depth of 11 inches, and Zone X_UNSHADED recorded 141 claims with an average payout of $13,578 and an average water depth of 4 inches. Homeowners, real estate agents, and journalists should pay the closest attention to properties located in Zone A and Zone X variants, where historical claims demonstrate both frequent inundation and significant average water depths indoors.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
12% of Delaware County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
2,284 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 10 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 1999, with 509 claims and $11.7M paid, the year of Hurricane Floyd Major Disaster Declarations.
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.
46 NOAA storm reports from Delaware County describe what happened, in the words of the forecasters who covered it. Read the Pennsylvania flood stories →
24 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 | 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 |
| Hurricane Katrina | Aug 29, 2005 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
273 since 1996: 144 flash floods, 71 river or area floods and 55 coastal floods or surges.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jul 31, 2025 | — |
| Flash Flood | May 30, 2025 | — |
| Flash Flood | May 16, 2025 | $10,000 |
| Flash Flood | May 16, 2025 | $15,000 |
| Flash Flood | May 16, 2025 | $20,000 |
| Flash Flood | Jul 9, 2025 | — |
| Flash Flood | Jul 9, 2025 | $5,000 |
| Flash Flood | Jul 9, 2025 | $25,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
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 · 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.
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 Delaware 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.