When gravity-based drainage isn’t an option, stormwater runoff and sewage flow are discharged mechanically. A sump pump is typically installed at the lowest point of the site or the basement level. For example, it can be used to prevent flooding or to drain water from a basement level to prevent hydrostatic pressure from building up on the basement walls, or it can be used to discharge the sewage flow to a higher elevation. The design flow and sump basin size are determined by fixture unit or hydrology calculations, and the discharge pipe head loss is determined by hydraulic calculations to size the pump system properly. Sump pump plans show the pump and basin position, elevation, the placement of intake and outflow pipes, remarks, details, and pump make and model specs.