Enter any address in Lee County, Illinois to see its FEMA flood zone
Flash flooding from thunderstorms is the dominant flood character in Lee County. Between 1993 and 2023, NOAA data recorded 18 flash flood events and 13 flood events. For example, torrential rainfall caused flash flooding across northern Illinois in August 2025, with estimated damages of $8.8 million in the region. More recently, scattered thunderstorms produced localized flash flooding on June 27, 2020.
National Flood Insurance Program (NFIP) claims data shows that properties in Zone A experienced the highest average payouts ($7,429) and the deepest average water depth (2.8 feet). Claims in Zone X also had significant payouts ($6,377) with an average water depth of 0.9 feet. Properties with unknown flood zone designations had the lowest average payout ($2,746) and water depth (0.6 feet).
Homeowners in areas designated as Zone A or Zone X, and those located near waterways susceptible to flash flooding, should pay particular attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
5 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Lee County, Illinois has recorded 31 flood-related events since 1996 according to NOAA's Storm Events Database, including 18 flash floods and 13 river or area floods. The county has received 10 federal disaster declarations, 4 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1973–2020)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Storms And Flooding | Flood | Feb 24, 2019 |
| Severe Winter Storm And Snowstorm | Snowstorm | Jan 31, 2011 |
| Snow | Snowstorm | Nov 30, 2006 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| Severe Storms & Flooding | Flood | Feb 23, 1985 |
| Blizzards & Snowstorms | Snowstorm | Jan 16, 1979 |
| Severe Storms & Flooding | Flood | Jun 10, 1974 |
| Severe Storms & Flooding | Flood | Apr 26, 1973 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Aug 18, 2025 | 0.00K |
| Flash Flood | Jun 27, 2020 | 0.00K |
| Flood | Jun 27, 2020 | 0.00K |
| Flood | Jan 21, 2020 | 0.00K |
| Flood | May 14, 2020 | 0.00K |
| Flood | May 30, 2019 | 0.00K |
| Flood | Mar 6, 2019 | 0.00K |
| Flash Flood | Aug 29, 2016 | 2.00K |
| Flash Flood | Aug 18, 2016 | 0.00K |
| Flash Flood | May 11, 2016 | 0.00K |
Flash Flood — Aug 18, 2025
During the afternoon and evening of the 18th, a few rounds of thunderstorms brought torrential rainfall to much of northern Illinois resulting in flash flooding. One particularly strong storm also produced damaging winds in DeKalb County. Initial reports estimate $8.8 million in flood damages around northern and northeast Illinois, and around $2.5 million in the city of Chicago alone.
Flash Flood — Jun 27, 2020
Scattered thunderstorms moved across portions of northeast Illinois during the afternoon of June 27th producing localized flash flooding.
Flood — Jun 27, 2020
Scattered thunderstorms moved across portions of northeast Illinois during the afternoon of June 27th producing localized flash flooding.
Flood — Jan 21, 2020
Flooding occurred along portions of the Rock River due to an ice jam.
Flood — May 14, 2020
Scattered severe thunderstorms moved across parts of northern Illinois during the late evening of May 14th. Additional thunderstorms produced heavy rain and localized flash flooding during the late evening of May 14th into the morning of May 15th. Some of the highest 48 hour rainfall totals ending Friday morning May 15th included: 4.75 inches near Sycamore; 4.71 inches near Park Ridge; 4.69 i...
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 Lee County, Illinois:
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 Lee County, Illinois 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.