ᐅ How many kilowatts should the pump in a wastewater lifting system for a single-family house have?

Hello everyone,

We need your help again:

Our house is located on a slope where there is no sewer line directly nearby. Our neighbor had the same issue and installed a lifting station (a shaft with a pump in the driveway). We now need the same system to connect to the existing sewer line.

We have received two quotes: one for a 2.2 kW pump and one for a 4 kW pump.

I don’t know if anyone can provide theoretical advice without seeing the site, but here are the details I have: Our wastewater flows into the shaft placed in our driveway. From there, the pump pushes the water over a distance of 120 meters (394 feet) on level ground to the connection point with the existing sewer line. From that point, the wastewater must travel 175 meters (574 feet) and overcome a vertical elevation of 16 meters (52 feet).

Since one pump has nearly double the power and therefore costs about twice as much, we would appreciate any tips or if anyone has a similar setup at home.

Thanks in advance.

Sizing is also a matter of quantity. How can one give a tip on that?

hampshire schrieb:

Sizing is also a matter of quantity. How can one give advice on that?

Can you specify a quantity? It’s a single-family house with 5 occupants (currently 3).

Well, there is a lot to say about this because, besides the number of people in the house, there are areas where surface water is also directed into the sewer. This is important for sizing.

Preventing backflow from the sewer is crucial. If the pump does not have to push the wastewater against sewer pressure and a very high flow rate due to surface water is not required, then the smaller pump is certainly sufficient.

hampshire schrieb:

Well, there’s a lot to consider here. Besides the number of people in the house, there are areas where surface water is also directed into the sewer. This is important for sizing.

Preventing backflow from the sewer is crucial. If the pump does not have to push the wastewater against sewer pressure and there is no very high flow rate required due to surface water, then a smaller pump should be sufficient.

Thank you in advance for your help...

The surface water does not enter the sewer; only the wastewater flowing through the drain does. The pipe from the pump to the sewer has a diameter of 32mm (1.25 inches), and this line is about 300 meters (985 feet) long, discharging directly into the sewer. Is there a way to calculate whether the pump capacity is sufficient for the vertical height and length the wastewater has to overcome?