Tricky wastewater situation on the slope (lifting station, backflow)

Hello everyone,

this is about our wastewater situation. We are building on a slope with one floor below the street. The following data are important for this:

Height of the basement (inhabited) with bathrooms, toilets, etc. 166.75m above sea level
Height of the sewer connection (bottom) of our property 166.42m above sea level
Height of the next manhole cover above our connection 169.69m above sea level

So the only option here would probably be a sewage lifting system. Does anyone have experience with this, can give tips or recommend something? What kind of costs should we expect?

Now there is also an alternative option via the lower-connected neighboring property (relatives, so no problem with permission/easement). This would mean 30m additional wastewater pipe, but the connection situation there is as follows:

Height of the sewer connection (bottom) 164.53m above sea level
Height of the next manhole cover above this connection 166.31m above sea level

Could we drain here without a lifting system and a backflow protection valve? Is it sufficient that the manhole cover at 166.31m is just under half a meter below our floor drains (e.g. shower) in the basement?

Thank you for your help. I would also be interested to know if there are still regulations to consider here.

Your builder at L

Hello

There is certainly also something with the connection obligation which speaks against this solution.

You will just have to arrange yourself with the lifting system that leads the wastewater once over your backwater level.
Wastewater from the upper floor can be drained directly.

Olli

So the slope should definitely be enough over the neighboring property. From 166.75m to the connection at 164.53m. It was more a question of the backwater level. This is at 166.31m...

Mandatory connection would of course be a knockout for this idea. Then the lifting station would have to be used...

Sorry, I had the heights wrong there