Everything about basements, pumps and water – clearly explained.

The height sewage can rise to when the sewer is overloaded – usually street level. Everything below it must be protected.

Required by municipal drainage bylaws for every drain below the backflow level. Yet many basements lack it – and it can fail even where it's installed.

Closes when the sewer backs up. Why water can still end up in the basement and how often it needs servicing.

Drainage, pump sump, lifting station, floor drains and backflow protection: the systems that move water out of your basement.

Almost always a moisture problem. Causes in the basement, ventilating correctly, what you can remove yourself and when to call a professional.

Which measures actually work – from backflow valves to smart monitoring – and which ones get expensive.

Every measure that keeps moisture out from the outside – from soil damp to pressing groundwater.

Waterproofing with an outer bitumen or plastic layer on the basement's exterior walls and floor slab.

All the pipes and fittings that carry a building's wastewater and rainwater into the sewer.

An underground system of perforated pipes in a gravel bed that carries seepage water to the pump sump. It doesn't help against high groundwater.

Controls the pump. If it sticks, the pump won’t start – and because the pump sits idle on many days, that often only shows with the next heavy rain.

Structural, technical and organisational measures against flooding – including in urban areas at risk of heavy rain.

Water entering normally dry rooms uncontrollably – through heavy rain, floods, sewer backflow or groundwater.

A drain set into the basement floor that takes in surface water. Below the backflow level, it's a direct entry point for sewage.

How to spot groundwater in the basement, what applies when pumping it out and how to keep an eye on the pump sump.

Can hit any house, not just near rivers: 1 in 10 homes was affected in 2002–2021, says the GDV.

Pumps wastewater from the basement into the sewer. If the pump fails, sewage backs up – and the alarm often only beeps in the basement.

An add-on to your buildings or contents insurance. Without it, damage from flooding and sewer backflow isn't covered.

Pipe water accounts for almost half of residential building insurance claims costs in Germany. Causes, first steps and who pays.

A closed pipe through which the submersible pump pushes water above the backflow level into the sewer.

Every basement pump fails eventually. The question is: will you notice in time? It usually happens quietly, at night or while you're away.

The central collection point for drainage water. If the pump fails or the float sticks here, costly water damage follows.

An overloaded sewer pushes wastewater back into the building's pipes – up through floor drains and toilets in the basement.

Which pump belongs in the basement, how to install it in the pump sump and how to retrofit an alarm for failures.

A heavy-rain claim cost €7,600 on average, says the GDV. Around 41% of homes have no natural hazard cover.

Water in your basement right now? What to do first, how to pump it out and where the water comes from.

They report water on the floor – standalone, over Wi-Fi or in a smart home. Which type suits what, and where the limit lies.

Measures the level in a pump sump or lifting station. Measuring principles, buying criteria and installation in the shaft.

A basement of watertight concrete (WU concrete): floor slab and walls carry loads and keep water out. Joints, penetrations and crack planning are what make it tight.

The recess in front of a basement window. In heavy rain it fills up – and becomes a weak spot.