Is backflow protection sensible in new construction above the backflow level without a basement?

Hello everyone,

we are currently planning our new building and our planning office brought up the topic of backflow prevention or rather a corresponding device suddenly appeared in the offer from the company that is creating the foundation slab.

Our house will be located above the backflow level and will be built without a basement. We are not located in a valley basin or similar.

Our planning office said it is absolutely necessary to install a corresponding protection (electric backwater pumping system, as sewage is involved). This is justified by the severe storms of recent years and water fountains shooting out of manholes and scenarios with 1.5m of water including mud and sand on the ground floor... I have the impression that it is also about their own legal protection.

The city, on the other hand, says that although there was a backflow in the sewer system in the region this summer due to heavy rain, they do not see any necessity for protection as we are located above the backflow level.

I am now torn—invest about €5,000 (+ regular maintenance etc.) or skip it and save the money.

I look forward to your opinions and experiences on this topic :)

Best regards

Willy

Is one flap not sufficient? Does it have to be the electric version with a pump? What does the insurance say? What needs to be included so that they pay in the event of a claim?

Hello, thanks for the reply! Unfortunately, a flap is not possible because of the feces-containing water. I have not received any feedback from the insurance yet. My suspicion (!) is precisely that the builder wants to protect himself, but I am really uncertain about the matter.

If you are above the backwater level, then it is really money thrown out the window. What is that supposed to do for you???