1,103 flood insurance claims·$30.8M paid·1 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 Williamson County, Tennessee. 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 rainfall dominates the flood risk profile in Williamson County, accounting for 73 events and 1 death compared to 24 standard flood events over the last 30 years. Recent NOAA storm records document significant weather events in the area, including a major severe weather and flooding event from February 15 to 16, 2025, and multiple rounds of thunderstorms on May 20, 2025, which produced large hail up to two to three inches in the county alongside five confirmed tornadoes.
National Flood Insurance Program claims data indicates that risk extends beyond high-risk areas. Zone A leads with 827 claims averaging $35,156 and an average recorded water depth of 7 inches. However, properties in lower-risk zones also experience losses; Zone X accounts for 179 claims averaging $28,465 with an average recorded water depth of 7 inches, Zone X shaded recorded 27 claims averaging $25,979 with an average water depth of 5 inches, Zone X unshaded recorded 25 claims averaging $36,348 with an average water depth of 3 inches, and unknown zones recorded 45 claims averaging $6,768 with an average water depth of 1 inch. Homeowners, real estate agents, and journalists should note that properties in both designated high-risk zones and standard Zone X locations experience damaging water depths averaging up to 7 inches.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
6% of Williamson County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
879 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 7 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 2010, with 439 claims and $18.0M paid, the year of Severe Storms, Flooding, Straight-line Winds, and Tornadoes.
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.
38 NOAA storm reports from Williamson County describe what happened, in the words of the forecasters who covered it. Read the Tennessee flood stories →
16 federal disaster declarations since 1974, 1 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Winter Storm | Jan 22, 2026 |
| Severe Storms, Straight-line Winds, Tornadoes, And Flooding | Apr 2, 2025 |
| Severe Storms, Tornadoes, And Flooding | Mar 25, 2021 |
| Severe Storms, Flooding, Straight-line Winds, And Tornadoes | Apr 30, 2010 |
| Severe Storms, Tornadoes, Straight-line Winds, And Flooding | Feb 5, 2008 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Storms, Tornadoes, And Flooding | May 4, 2003 |
| Severe Storms, Tornadoes And Flooding | May 5, 1999 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
97 since 1996: 73 flash floods and 24 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | May 20, 2025 | — |
| Flash Flood | Feb 15, 2025 | — |
| Flash Flood | Apr 5, 2025 | — |
| Flash Flood | Apr 3, 2025 | — |
| Flood | Apr 3, 2025 | — |
| Flood | Aug 26, 2023 | — |
| Flood | Jul 19, 2023 | — |
| Flood | Dec 7, 2022 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · May 20, 2025. Multiple rounds of thunderstorms impacted Middle Tennessee on May 20, 2025. The first round of thunderstorms was a decaying mesoscale convective system (MCS) that produced damaging winds which downed a few trees. The next round was discrete supercells which produced large hail, damaging winds, and tornadoes. The largest hail reported during this event was in Williamson County where hailstones of two to three inche…
Flash Flood · Feb 15, 2025. A major severe weather and flooding event unfolded across Middle Tennessee on February 15-16, 2025. As well above average moisture spread into the area, this helped set the stage for very heavy rainfall across Middle Tennessee. Showers and thunderstorms began early during the day on February 15th, and the primary threat with this first round was flooding. The most significant flooding was reported in Montgomery an…
Flash Flood · Apr 5, 2025. A major and historic multi-day severe weather event unfolded across Middle Tennessee during early April 2025. This event began during the afternoon hours of April 2nd and continued through April 6th. These first couple rounds of thunderstorms brought damaging winds and large hail along with a tornado risk. The corridor from southwest Middle Tennessee into the Nashville metro area was hit particularly hard with mul…
Flash Flood · Apr 3, 2025. A major and historic multi-day severe weather event unfolded across Middle Tennessee during early April 2025. This event began during the afternoon hours of April 2nd and continued through April 6th. These first couple rounds of thunderstorms brought damaging winds and large hail along with a tornado risk. The corridor from southwest Middle Tennessee into the Nashville metro area was hit particularly hard with mul…
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 Williamson 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.