ᐅ Is a backwater valve useful for new construction built above the backflow level without a basement?

Hello everyone,

We are currently planning our new build, and our design firm brought up the topic of backflow protection. Suddenly, a related device appeared in the offer from the company that is constructing the foundation slab.

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

Our design firm says it is absolutely necessary to install appropriate protection (an electric backflow pumping system, since sewage is involved). Their reasoning is based on severe storms in recent years, with water gushing from manholes and scenarios involving 1.5 meters (5 feet) of water mixed with mud and sand on the ground floor. I get the impression, though, that legal liability concerns are also part of the motivation.

The city, however, says that although there was backflow in the sewer system in the region this summer due to heavy rainfall, they see no need for protection since we are above the backflow level.

I am torn — invest about €5,000 (plus regular maintenance, etc.) or leave it out and save the money.

I look forward to your opinions and experiences on this topic 🙂

Good luck

WillyW0nk4

Is a flap not sufficient? Does it have to be the electric version with a pump? What does the insurance say? What has to be installed for them to cover in case of damage?

Hello, thanks for the reply! Unfortunately, a flap is not possible due to the wastewater containing fecal matter. I have not received any feedback from the insurance company yet.

My suspicion (!) is that the building planner wants to cover themselves, but I am really uncertain about this issue.

If your property is above the backflow level, then it is truly money down the drain. What benefit would that even bring you???