ᐅ Challenging wastewater situation on a slope (lifting station, backflow prevention)

Created on: 18 Oct 2019 10:05
B
Bauherr am L
B
Bauherr am L
18 Oct 2019 10:05
Hello everyone,

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

Height of the basement (occupied) with bathrooms, toilets, etc.: 166.75 m above sea level (547.6 ft)
Height of the sewer connection (invert) on our property: 166.42 m above sea level (546.4 ft)
Height of the nearest manhole cover above our connection: 169.69 m above sea level (557.0 ft)

So, it seems that only a sewage lifting station would work here. Does anyone have experience with this, can offer advice or recommend options? What kind of costs should we expect?

There is also an alternative option through the neighboring property with a lower sewer connection (relatives, so no issue with permission or building encumbrance). This would mean an additional 30 m (98 ft) of wastewater piping, but the connection situation there is as follows:

Height of the sewer connection (invert): 164.53 m above sea level (539.9 ft)
Height of the nearest manhole cover above this connection: 166.31 m above sea level (545.7 ft)

Would it be possible to drain here without a lifting station and backflow prevention valve? Is it sufficient that the manhole cover at 166.31 m is just under half a meter below our floor drains (for example, shower) in the basement?

Thank you for your help. I would also be interested to know if there are any regulations we should be aware of.

Best regards,
Bauherr am L
wrobel18 Oct 2019 10:49
Hello

There is certainly also an obligation to connect that speaks against this solution.

You will have to manage with the lifting station that pumps the wastewater above your backflow level.
Wastewater from the upper floor can be discharged directly.

Olli
B
Bauherr am L
18 Oct 2019 10:54
The slope should definitely be sufficient over the neighboring property. From 166.75 m (547.2 ft) at the connection point down to 164.53 m (540.0 ft). It was more a question of the backwater level, which is at 166.31 m (545.8 ft)...

A mandatory connection would obviously be a dealbreaker for this idea. Then a sewage lifting system would be necessary...
wrobel18 Oct 2019 11:26
Sorry, I got the heights wrong there.