A sewage lift pump system allows sewage to be moved onto higher levels of land, as opposed to the typical gravity system that moves sewage from high to low elevations.
An underground hole, or wet well, houses the sewage from various buildings. Once the level of sewage reaches a set point, a lift is powered and moves the sewage upward through pipes called the "rising main" or "sewer force main." After being lifted out, the sewage travels to a gravity manhole and eventually to a facility for water treatment.
A wet well is equipped with multiple pumps for movement of the sewage so that if one pump fails, another can finish the job. This backup system keeps the sewage from overflowing a wet well.
The fumes within a wet well are noxious and dangerous for humans to breathe in, so minimal time near a wet well for maintenance is suggested.