Pump knowledge

Sewage Lifting for Villa Renovations: Adding a Bathroom Below Sewer Level

Adding a bathroom in a villa basement is one of the most common renovation wishes — a guest washroom, a gym shower, a laundry or a small kitchenette on a floor that was never meant to have plumbing. The obstacle is simple: that floor usually sits below the municipal sewer line, so wastewater cannot drain away by gravity. The answer is not to dig up the whole house or reroute the main drain. It is to install a sealed sewage lifting station placed close to the new fixtures: wastewater collects in the tank, and when the level reaches the start point the pump lifts it up into the main sewer pipe, then stops automatically as the level falls. Whether the renovation works quietly for years depends less on the pump itself than on four decisions made before the tiles go on and the walls are closed.

First, survey before you select. Confirm three things on site: where the main sewer connection is and how high it sits, the vertical lift plus the horizontal distance from the station to that connection, and the full fixture list — WC, basin, shower, washing machine and air-conditioning condensate, and how many of each. The required head is the vertical lift plus friction losses in the discharge pipe, and a long run with several bends loses more head than most owners expect. Send the lift height and pipe distance to the manufacturer and have an engineer confirm the model from the pump curve in writing, rather than choosing from the maximum head figure alone.

burks B-Lift sewage lifting station for villa basement bathroom renovation

Second, for a renovation, prefer an external-pump layout. On the burks B-Lift series the pump sits outside the tank, so inspection and servicing are dry — nobody has to reach into collected sewage to reach the pump. The series adds automatic tank back-flushing, dual level control by pneumatic sensing backed by a float, a built-in check valve, and an IP68 rating for the unit itself, excluding the control box. A villa basement is used intermittently but must never flood a finished floor, and that maintainability matters more over ten years than a small difference in purchase price.

Third, size the tank by fixtures, not by floor area. One bathroom group — WC, basin and shower — plus light grey water is a 28-litre job, covered by the B-Lift 28L at 0.85 kW. Add a laundry or a second bathroom and step up to 55 litres at 1.2 kW. If the basement carries several fixtures in heavy guest use, or the floor simply cannot be out of service, choose the 100-litre duplex station: its two pumps alternate duty, run together at peak inflow, and if one faults the other takes over automatically while the controller raises an alarm.

Fourth, fix the pipework before the finishes. B-Lift tanks carry reserved DN100 and DN40 inlets — open only the ones you connect and leave the rest sealed. Inlet pipes need a downward slope of about 3 percent, the WC drain must sit higher than the centre of the inlet, and a shower outlet should be at least 200 mm above the tank bottom, ideally with a filter to catch hair. The DN40 vent pipe must be connected and taken above the roof or outdoor planting; an unvented tank builds pressure and drains poorly. The discharge line uses the built-in check valve plus a stop valve. Finally, leave real access space around the unit for inspection and removal — never box a lifting station in so tightly that it cannot be serviced.

Fifth, respect the electrical and usage limits. Installation must include a leakage circuit breaker, wiring belongs to a qualified electrician, and power must be switched off before any installation or maintenance work. A lifting station is for domestic sewage, including WC waste with toilet paper — strong chemical solvents and hard objects such as stones or metal must never be discharged into it. Keep the unit powered in normal use, and do not drain water into it while it is switched off.

Planning a renovation like this? Send us your fixture list, the lift height, the distance to the sewer and a floor plan or site photos through the inquiry form on this site, by WhatsApp or by email, and our engineers will return a written selection. You can also make a first check yourself with the online pump selection tool on this site.