When a washing machine, shower or toilet is located in the basement, it is important to consider how the wastewater will be discharged. This is because a drainage point in the basement is usually below the backwater level. This means that the wastewater cannot flow down a natural gradient to the sewer, as with a gravity system, but has to be pumped up with a lifting station or pump. In addition to the pumping height, the type of wastewater is an important criterion when choosing a suitable product: black water (wastewater with sewage) always requires different solutions than grey water (wastewater without sewage).