Pump knowledge

How to Size a Sewage Lifting Station for a Basement Bathroom

When a basement bathroom, kitchenette or laundry sits below the municipal sewer line, wastewater cannot drain by gravity. A sealed sewage lifting station collects it and pumps it up to the main drain. Sizing one is not guesswork — work through three things: how much water, how high, and what is in it.

burks B-Lift sewage lifting station for basement bathroom

Step 1 — Count the fixtures. One bathroom group (WC, basin, shower) plus light grey water is a 28-litre job: the burks B-Lift 28L (0.85 kW) is built for exactly that. Add a laundry or a second bathroom and step up to 55 litres (1.2 kW). For a restaurant, clinic, office or public washroom — anywhere a failed pump becomes a flood and a closed business — choose the 100-litre duplex station: two pumps alternate duty, both run together at peak inflow, and on a fault the healthy pump takes over automatically while the controller alarms.

Step 2 — Work out the head. Head is the vertical lift plus friction losses in the discharge pipe. Compare it against the station's maximum head and keep margin: the B-Lift family reaches 14 m, comfortable for a typical basement lift of 3–6 m, but a long pipe run with several bends eats head quickly. The safe way is to send the lift height and pipe distance to the manufacturer and have an engineer confirm the model from the curve, in writing, before you order.

Step 3 — Match the pump to the sewage. Ordinary domestic sewage suits a vortex impeller with a generous free passage (55 mm on the B-Lift) that passes solids instead of trapping them. Where the sewage carries wipes, fibres and sanitary solids — cafés and small commercial sites, typically — a cutter pump is the safer choice: the burks BN-Lift shreds solids before pumping, with a 60 mm passage behind the cutter.

Two details are easy to miss and expensive to retrofit. First, plan the inlets: B-Lift tanks carry reserved DN100 and DN40 inlets — connect what you need, the rest stay sealed. Second, the vent pipe (DN40) must be connected; an unvented tank builds pressure and drains poorly. Level control also matters over time: stations with dual control (pneumatic sensing backed by a float) and automatic tank back-flush keep working when a single float would foul.

Send us the fixture list, the lift height and the distance to the sewer, and our engineers will return a written selection — or size it yourself first with the online pump selection tool on this site.