Grundfos Drainage pumps are used to drain pits and deep roadway underpasses, as well as to dewater basements and courtyards that are at risk of flooding or groundwater. Float switches are typically used to start it automatically. The water to be handled may contain dirt and solids, the particle size of which is determined by the pump size and impeller. Drainage pumps are the most effective way to prevent basement flooding. They are classified into three types: jet pumps, effluent pumps, and utility pumps.