Key facts: Wilmington
- The city sits where the Christina River and Brandywine Creek meet near the Delaware River,[1] and Ida showed in 2021 what that position can mean.
- After Ida's remnants passed in September 2021, Brandywine Creek crested at 23.14 feet in Wilmington, beating the 2014 record of 20.43 feet.[2]
- University of Delaware researchers put peak flow at 33,700 cubic feet per second, above the 1972 Agnes record.[3]
What Ida changed on the Brandywine
After Ida's remnants passed in September 2021, Brandywine Creek crested at 23.14 feet in Wilmington, beating the 2014 record of 20.43 feet.[2] University of Delaware researchers put peak flow at 33,700 cubic feet per second, above the 1972 Agnes record.[3] Flooding ran between I-495 and Market Street, worst across 15 to 20 blocks along the creek.[2]
A closer look in Wilmington
Mill-era buildings need slower drying
Mills lined the Brandywine for its fast water, and the neighborhoods around them are old.[1] Masonry walls hold water for a long time and release it slowly, so aggressive heat can crack finishes. Ask for moisture readings that show progress, and a plan for mechanicals in the cellar.
Flood claims recorded in New Castle County
Wilmington sits in New Castle County. FEMA publishes every National Flood Insurance Program claim with personal details removed, which gives a plain record of where water has reached insured buildings here.
| Measure | Count |
|---|---|
| Flood insurance claims on record | 1,575 |
| Year with the most claims | 2003 (263) |
| Largest named event | Hurricane Floyd (210) |
| Claims outside high-risk A and V zones | 32% |
| Claims on buildings built before 1975 | 80% |
County-wide counts of insured claims only. Uninsured losses, burst pipes and appliance leaks are not in this data.
What the Wilmington claim record shows
For Wilmington homes, the local precedents are the events behind the most New Castle County claims: Hurricane Floyd (210 claims), Hurricane Irene (144 claims) and Hurricane Ida (90 claims).
About 32% of claims with a recorded zone came from outside the high-risk A and V zones, so a moderate-risk label does not mean a Wilmington home stays dry.
If your Wilmington home is older, note that buildings from before 1975 make up 80% of county claims with a known build date. Many predate current flood maps, so inspect low outlets, ductwork and subfloors closely after any water event.
Federal disaster history for New Castle County
FEMA lists 17 federal declarations covering New Castle County. The most common types are hurricane (9), snowstorm (4) and biological (2). The latest are Remnants of Hurricane Ida in 2021, Tropical Storm Isaias in 2020 and Covid-19 Pandemic in 2020. When a declaration is open, federal aid may be available to Wilmington residents, so ask about it alongside your insurance claim.
Wilmington weather and your home
Weather records for Wilmington from 2015 through 2024 average 52 inches of precipitation a year, and August and July are the wettest months. The area averages 11.5 days a year with an inch or more.
Wilmington falls to 20°F or below on about 14 nights a year, which puts pipes in exterior walls, crawl spaces and garages at risk.
When rain falls in Wilmington
Seasonal averages for Wilmington, 2015 through 2024. Plan roof, gutter and sump pump checks before the wettest stretch.
| Season | Average | Share of year |
|---|---|---|
| January to March | 11.6 in | 22% |
| April to June | 13.8 in | 26% |
| July to September | 15.1 in | 29% |
| October to December | 11.6 in | 22% |
Modeled from Open-Meteo historical weather data. Precipitation includes rain and melted snow.
Wilmington home checklist from these records
- Don't rely on recent quiet years. Only 15% of New Castle County claims date from 2015 or later, so older floods still show what can happen.
- Insulate exposed pipes before 14-plus hard-freeze nights arrive, and know your main shutoff.
- Test any sump pump before August, since Wilmington averages 12 days a year with an inch or more.
- Keep dated photos of each room. After Hurricane Floyd, 210 insured New Castle County owners filed claims at about the same time.
What to tell the Wilmington contractor
- How close you are to Brandywine Creek or the Christina
- Whether the water was creek water or from inside the home
- Whether the furnace or panel got wet
Services Wilmington callers ask about
Questions
Wilmington water damage questions
Was my Wilmington address in the Ida flood zone?
Check your address on the state's flood planning tool and FEMA maps, since the worst damage was concentrated along the creek.
Is creek floodwater dangerous indoors?
Yes. Treat it as contaminated, keep clear of wet electrical equipment, and wear protection during any cleanup.