Floods: how to prepare, what to do when the water comes and how to return home

Floods are the most common natural disaster worldwide. In recent years, catastrophic flooding has hit Germany and Belgium (2021), Pakistan (2022), Libya (2023), Valencia in Spain (2024) and Central Europe (2024). Unlike earthquakes, floods usually come with a warning, and a few hours of preparation make an enormous difference.

Before: know your risk

• Find out whether you live in a flood zone. Your local authority or the national flood agency publishes risk maps. Think about history too: has water ever reached your garden or basement?
• Check your insurance covers flooding, and for how much.
• Keep important documents high up in a waterproof bag and make digital copies.
• Clear gutters and drains before the rainy season.
• Fit a backflow valve on your drains if you live in a house and sewage has ever backed up.

Warnings: what the colors mean

Many countries use color-coded warnings:

• Yellow: dangerous weather possible. Keep an eye on the news.
• Orange (amber): dangerous weather likely, with high intensity. Get ready to act.
• Red: very intense, dangerous weather. Follow the authorities’ instructions immediately.

When you get a warning

• Move documents, medicines, electronics and valuables upstairs or onto high shelves
• Check your go bag and charge phones and power banks
• Fill some containers with drinking water (the mains supply can become contaminated)
• Bring in or tie down garden items that could be swept away
• Move the car to higher ground
• Be ready to shut off gas, electricity and water
• Put sandbags or flood barriers at doors, if you have them

If you’re told to evacuate

Leave immediately, by the route the authorities give. Shut off gas, electricity and water, lock the door and take your go bag. Don’t go back for forgotten things. Tell your out-of-town contact where you’re going.

If the water catches you at home

• Go upstairs or into the attic. Take water, a flashlight, your phone and a blanket.
• Don’t climb into a closed attic with no way out; if the water keeps rising, you need access to the roof.
• Signal your presence with a flashlight or a brightly colored cloth.
• Call the emergency number and say how many people are there and on which floor.

On the road

Never drive into water covering a road, even if it looks shallow. You can’t see whether the road underneath is still there, and 30 cm (1 ft) of moving water can lift and carry away a car. Turn around and find another route.

On foot, even 15 cm (6 in) of moving water can knock you down. Floodwater is almost always contaminated with sewage, fuel and debris, and may hide open manholes or live electric cables.

After: returning home

1. Go back only when the authorities say it’s safe.
2. Don’t go in if you see cracks in the walls, washed-out foundations or smell gas.
3. Don’t turn the power back on until an electrician has checked the wet wiring.
4. Photograph the damage before cleaning up, for your insurance.
5. Throw away food that has touched floodwater, including bulging or rusty cans.
6. Don’t drink well water until it has been disinfected and tested.
7. Wear boots and gloves to clean up, ventilate well and dry the house quickly to prevent mold.
8. Tetanus: if you’re injured during the cleanup, ask a doctor whether you need a booster.

For safe drinking water after a flood, read emergency water purification.