Can I drive or walk through this flood water?
As of 2 November 2026, the US National Weather Service says 6 inches (15 cm) of fast-moving flood water can knock over an adult, 12 inches (30 cm) of rushing water can carry away most cars and 2 feet (60 cm) can carry away SUVs and trucks; UK agencies give the same 15 cm, 30 cm and 60 cm lines. Whatever the depth, do not drive or walk into flood water.
How deep is the water?
Don't. 30 cm (12 in)
Do not drive in: moving water at this depth can float a car.
Rule: US National Weather Service, Turn Around Don't Drown, checked 2026-11-02
Rule: Natural Resources Wales, What's in floodwater? (information sheet), checked 2026-11-02
Rule: Environment Agency, Driving complacency press release, 19 Dec 2019, checked 2026-11-02
What is under the water
Natural Resources Wales lists what flood water hides:
- Raised manhole covers, kerbs and steps you cannot see.
- Broken glass, nails and metal carried in the water.
- Sewage, farm run-off, fuel and chemicals.
- Electricity, if power lines have fallen into the water.
The National Weather Service, citing CDC, says over half of all flood-related drownings happen when a vehicle is driven into hazardous flood water.
The official linesWhat each depth of moving water can do
| Depth | Inches | What it can do | Who says so |
|---|---|---|---|
| 15 cm | 6 in | Fast-flowing water can knock a person off their feet. | Natural Resources Wales; NWS: "6 inches of fast-moving flood water can knock over an adult" |
| 30 cm | 12 in | Moving water can float the average family car. | Environment Agency; Natural Resources Wales; NWS: "12 inches of rushing water" carries away most cars |
| 60 cm | 24 in | Moving water sweeps most vehicles away, SUVs and trucks included. | Natural Resources Wales; NWS: "2 feet of rushing water" carries away SUVs and trucks |
Worked examplesEvery depth gets the same answer
| Depth | Inches | Answer |
|---|---|---|
| 5 cm | 2.0 in | Don't. Still do not enter: you cannot see the current, open drains, broken road or contamination under it. |
| 10 cm | 3.9 in | Don't. Still do not enter: you cannot see the current, open drains, broken road or contamination under it. |
| 15 cm | 5.9 in | Don't. Do not walk in: fast water at this depth can knock an adult over. |
| 20 cm | 7.9 in | Don't. Do not walk in: fast water at this depth can knock an adult over. |
| 30 cm | 11.8 in | Don't. Do not drive in: moving water at this depth can float a car. |
| 45 cm | 17.7 in | Don't. Do not drive in: moving water at this depth can float a car. |
| 60 cm | 23.6 in | Don't. Do not drive in: moving water at this depth sweeps most vehicles away, SUVs and trucks included. |
| 90 cm | 35.4 in | Don't. Do not drive in: moving water at this depth sweeps most vehicles away, SUVs and trucks included. |
Related on Global Incident Tracker
Flood warnings now (UK) Are rivers rising near me? Weather alerts by state (US) Why shallow flood water kills Never drive through flood water Electricity in flood water
What this page shows, and what it misses
It puts a depth you type next to the depths at which official agencies say moving water knocks people over and floats or sweeps away vehicles. It cannot measure water: flood water is usually deeper and faster than it looks, still water can start moving, and a road can be washed away underneath. The drawing is a simple illustration, not a model of any real car. The answer is always the same: do not go in.
Quoted from the US National Weather Service (public domain), Environment Agency (Open Government Licence v3.0) and Natural Resources Wales.