There are three possible reasons for this:

1. Inadequate building sealing or insulation from the ground.
2. Carelessly designed or constructed basement doors, windows, or light wells. 
3. Sewage that can back up through the house connection.

From the outside, for example, by adding an extra step in front of the basement door. Protecting your sanitary facilities is also not rocket science. Often, installing a simple backflow preventer is sufficient. However, we strongly recommend a lifting system. In this case, it is essential that you consult a specialist.

Yes, there are. Backflow preventers must not only be installed professionally, but also serviced regularly. At least twice a year. You should take both of these things seriously. Otherwise, your insurance company may reduce the amount it pays out for damage or, in the worst case, cancel your policy altogether.

They are obliged to plan and construct the sewage network in accordance with legal rules and regulations. They must then inspect the facilities accordingly and repair them if necessary. And that is exactly what we do.

The sewer system is designed to easily handle rainfall that is so heavy and rare that statistically it only occurs every five years. However, this also means that in the event of more extreme storms, the sewer system can and may fill up to the so-called backflow level (= top edge of the road).

This would also require the existing sewer network to be adapted accordingly. And that is simply impossible. But even if such an "expansion project" were technically feasible, it would not make economic sense. Larger sewers mean higher investment and maintenance costs, and thus higher fees. And there is another factor that speaks against it: during dry periods, some of the dirt would remain in the sewers because the water pressure would be too low to flush it completely to the sewage treatment plant. This would result in a foul odor coming from the drains.