Electric backflow stopper for toilets below the backflow level?

Hello everyone,

our ground floor is located below the backwater level. However, there is sufficient slope from our wastewater pipe at the house to the wastewater pipe of the street. Is it allowed to drain with an electric backwater valve and slope? Or do we necessarily have to use a lifting system to get above the backwater level? I am aware that the standard [DIN EN 12056] exists, according to which only rooms with subordinate use are permitted this way. However, the question is when this standard must be applied. We live in Hamburg. Is compliance with the standard mandatory there? Or is it prescribed nationwide?

Thank you for your help
wagib

To my knowledge, there are also electric backflow valves with built-in pumps, such as the Pumpfix from Kessel. In the event of backflow, it pumps the wastewater against the backflow. In that case, no lifting system should be needed anymore.

We would need this in case we created a separate apartment in our basement, so that the toilets can still be used in the event of backflow.

Why should one continue to pump feces into an already overloaded sewer system in the event of backflow?

Because you "have to". ;-) It happens anyway for all people who are above the backwater level. It is even required by the standard I mentioned that you are able to do this.

: I took a look at the Pumpfix. There is also a building supervisory approval from DIBt, according to which the following applies: "The installation is subject to the conditions of DIN EN 12056-4. Deviations from the above-mentioned standard section 4, last paragraph, must not lead to the use of the outlets connected to the backwater pump system being abandoned." Which ultimately means that the backwater is pumped against. However, DIN EN 12056-4 states in this paragraph: "A backwater valve can be used if - there is a slope to the sewer, - the rooms are of secondary use, i.e., no significant property or health of the occupants is affected by flooding of the rooms, - the user group is small and has a toilet above the backwater level available, - in case of backwater, the use of the outlet can be foregone." This means that it must still be a room of secondary use and the user group must be small and a toilet above the backwater level must be available. Unfortunately, this does not apply to me.

Deviating from this DIN, it is assured that the toilets can be used. The DIN probably does not yet know about the Pumpfix. How it looks in this case, of course, I do not know ;)