A sump pump is nothing but a pump which is used to pull out water that accumulates in a collecting sump sink (normally set up in the basement of buildings). This water may come in from the outside drains of the cellar waterproofing system because of storm water or ground water, and if your basement is located beneath the water table.
These pumps are used when a basement overflows every now and then. This helps in solving dampness, in cases when the water table is at a higher level than that of the foundation of your home. Such pumps direct water away from your house to any other place where it does not cause problem to anyone, like a dry well or the municipal rain water drain.
Pumps may release the discharge to the sanitary sewer in case of older installations. But once these systems are considered, they can be acceptable. However, this method may violate municipal bylaws or the plumbing code, as it can devastate the municipal sewage system of water treatment. Municipalities are requesting land owners to detach and reroute the discharge from the sump away from sanitary drains. Many landowners have inherited the sump discharge conformations and they do not realise that the discharge from the sump are taken to the sewer. On the other hand, if the discharge is directed to the laundry basin, then it is probably going to the sewer.
These pumps are usually hardwired in the electrical system of a home but these machines sometimes have battery backup. The pressurized water supply of the home powers up the pumps, eliminating the necessity for electrical energy at the cost of using clean water. As a sump sink may overspill if not pumped constantly, a backup scheme is vital for situations when the main power goes out for long period of time, as in during a heavy storm.
There are mainly two types of pumps to drain out sump water, i.e. pedestal pump and submersible pump. The motor of the pedestal pump is fixed above the sump so that it can be easily serviced, and be more conspicuous. The impeller of the pump is driven by long, vertical shaft. The submersible pump is completely mounted in the inside of the sump, and is particularly sealed so as to avoid electrical short circuits. However, there is huge debate about which type of pump is superior.