Though a sump pump can be used for other purposes, the two most common uses involve the removal of ground water from around the perimeter of a building foundation or the pumping of laundry discharge to a higher-level drain connection. In the case of the former, such an installation prevents seepage and flooding into basements and crawl spaces. Unlike most of the products covered in this course, sump pumps tend to be somewhat regional in their application: standard equipment in certain areas of the country, rarely used in others. Another way to define this is based on the construction of the foundation - whether or not there is a basement (or sub-grade crawl space).
THE SYSTEM:Before we look at the mechanical makeup of these products, let's look at the input and output aspects of an installation used for discharging ground water. First of all, if the sump pump is to dispose of ground water drainage, there must be a network of piping in the ground around and/or under the house to collect it. This usually takes the form of a loop of drain tile around the foundation. Drain tile is loosely jointed or perforated drainage piping material, constructed of clay, composition or plastic, which permits ground drainage to seep in. Such a loop is usually laid just outside the foundation footing in the case of new construction, or just inside the footing in the case of a retrofit installation. The water seeping into the drain tile is collected in a pit, called a sump. In the overall water-draining network, the sump is positioned at the lowest point, using gravity to get the water there. This water is removed by the pump when the level in the pit rises to a predetermined level, causing the float switch to activate. As the level drops, the float switch cuts out again, completing the cycle. Water is evacuated outside the building through a discharge line (most codes do not allow direct connection to the sanitary sewer system for ground water discharge). Laundry sump pump systems, on the other hand, do discharge into the sanitary sewer.
Let's move on now to examine each of the basic components in a typical sump pump installation.