Risk of heavy rain: How to protect your home and yourself

Heavy rain can fall almost anywhere

Anyone who lives on the Danube or Rhine has already dealt with the issue of flooding. But far away from the large rivers, basements can also flood: due to heavy rain. This can basically pour down anywhere in Germany and cause considerable damage. Small rivers can suddenly swell into raging torrents; but sealed ground, a location on a slope or in a hollow can also concentrate the rain into a flood wave that overwhelms the local sewer system – or pushes it directly into the house. With climate change, such weather events are likely to become even more severe over the years.

The municipalities inform about endangered areas

If you enter the name of your municipality and “heavy rain map” into your internet browser, you will usually find an interactive map showing the path the water is taking. This allows you to estimate how at risk your own house is. North Rhine-Westphalia is exemplary: the state has combined all municipal maps, although municipal maps often have a better resolution.

Short warning times make quick action difficult

Unlike river flooding, it is difficult to predict where heavy rain will cause flooding. It is therefore important to take long-term preventive measures. Where it makes sense to place sandbags in front of the entrance to the underground car park or the basement windows in case of an emergency, these should always be kept ready. The weak points of the house should also be identified and remedied (see below).

Never stomp into a flooded basement

You shouldn’t give in to this impulse to save something quickly. At the beginning of May, a man in Hausen (near Würzburg) died of an electric shock when he climbed down into his cellar. As soon as the water reaches sockets or electrical devices, there is an immediate risk to life. It can therefore be worthwhile to switch off the power in the cellar as a precaution before the storm.

Water pressure is also tricky: once the water is in the basement, doors can sometimes no longer be opened against the pressure of the water.

Prepare the cellar in good time before heavy rain

Valuable items should not be stored in the basement. Sockets should be installed above and no multiple sockets should be dangling down. Used oil or half-open paint pots can also have a bitter revenge if water gets into the basement. A basement that can get damp should be painted or tiled with waterproof paint instead of wallpapering it.

Protect the house against backflow

When it pours with rain, the sewage drains fill up. Rainwater and sewage usually flow together into one sewer. If this is overloaded, the sewage can no longer flow away, pushes back into the basement – and can even come out of the drains further up in the house. That’s why the house must be properly protected with a backflow valve or a lifting system. This is usually also mandatory.

Nevertheless, insurance experts report that in the majority of the houses they inspect, this protection against backflow is not sufficient. The backflow of wastewater after heavy rain is by far the most common cause of damage. And the best protection is of no use if it is not regularly maintained. A common reason why the flap does not close properly is rubbish that has been carelessly thrown into the toilet. Panty liners, diapers or food scraps can get stuck in the flap.

Who pays if heavy rain causes damage

Household contents and building insurers cover damage in the basement. The former covers the furnishings and belongings, the latter covers the building. However, only if natural hazards are also insured. Some insurers exclude damage caused by backflow even then, warn consumer advice centers. So it’s better to check the small print!

Avoid trouble with the insurance company

If the house is flooded, residents should do what they can to limit the damage – as long as it is safe to do so (see above). This is what insurers require. Before doing so, however, it is important to document the damage in detail with photos and videos, otherwise it may be difficult to get reimbursement. It is also advisable to document the maintenance of the backflow prevention device.

Preparing basement windows

The light shafts in cellars are often a sore spot: they usually have no water drainage, so a small pool forms in the shaft from which the water presses against the pane. Either the panes have to be pressure-resistant or the light shaft has to be protected with flaps or walled in.

Clean gutters regularly

Gutters are often not cleaned and leaves and moss accumulate. Many people think that this is not a problem, but the water often finds its way into the roof, onto balconies or other places where it can press into the house. Sometimes in old houses there are old drains that direct water from outside into the house drain. If the backflow then works as well as desired, this water cannot drain away and runs into the house via the drains.

Heavy rain gateway underground car park

In Idstein, Hesse, the underground car park of a police station recently filled up so quickly that the garage door could no longer be opened. In inner cities, new buildings are increasingly being fitted with underground car parks. The access ramp is often a gateway for heavy rain, as the small collecting channel at the entrance is not designed to handle large amounts of water. It becomes dangerous when an electric car is also charging at the wall box – and the water running in could potentially become electrified.

It is also important not to endanger yourself in the underground car park. The Flood Competence Centre recommends that you do not drive your car out when the water level is ten centimetres or more.

Checklist for protection against heavy rain

Anyone who wants to protect their home against heavy rain should first check the level of risk using the municipal maps (see above). There are also useful checklists that allow you to systematically work through all the possible points of attack. These are particularly useful from the consumer advice centers and the flood competence center.

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