6inches
of fast-moving water can knock an adult off their feet and sweep them away.
Most vehicles begin to lose contact with the road in about 6 inches of water.
How much water can carry away a car?
Less than most people think. The National Weather Service gives three numbers. For big vehicles, its own pages give two different ranges — this page leads with the lower one, and prints the other one right under it. Read them, remember them, and never test them yourself.
12inches
of moving water can carry away a small car.
12–18inches
of flowing water can sweep away vehicles — including pickups and SUVs.
That is the lower figure, from a local National Weather Service office page: vehicles “can be swept away in 12-18 inches of flowing water. This includes pickups and SUVs.” The national NWS flood safety brochure gives a higher range: 18 to 24 inches of moving water can carry away larger vehicles including trucks, vans and SUVs. Both ranges are printed here, each with its source — and this page leads with the lower one. Better to be safe.
It is NEVER safe to drive or walk through flood waters.
What the National Weather Service wants you to know
- Driving in is how most people die. More than half of flood-related deaths happen when someone drives into flood water.
- You cannot tell how deep it is. You cannot tell how deep the water over a road really is, and the road underneath may be washed out or collapsed.
- Never drive around barriers. Barriers are there to block a flooded road. Never drive around them — turn around, or cancel, delay, or reroute the trip.
- Night is more dangerous. Be extra careful at night, when flood dangers are harder to recognize.
- Get to higher ground. If flooding happens, get to higher ground and stay out of dips, low spots, and drainage areas.
The only safe answer
If you see water over the road, there is only one safe move: turn around. Do not drive in. Do not walk in. Find another way, or wait.
Turn Around Don’t Drown®
Sources
All facts and figures on this page come from the National Weather Service (weather.gov):
The national flood safety brochure, Flood Safety for You and Your Family — 6 inches of fast-moving water can knock adults off their feet and sweep them away; 12 inches of moving water can carry off a small car; 18 to 24 inches of moving water can carry away larger vehicles including trucks, vans and SUVs.
A local National Weather Service office page (Central Illinois), Flood Safety Awareness Week — Turn Around Don’t Drown — most vehicles begin to lose contact with the road in six inches of water, and vehicles can be swept away in 12–18 inches of flowing water, including pickups and SUVs.
The national Turn Around Don’t Drown page.
Checked against the National Weather Service on November 3, 2026.