A sump is a low space that collects any often-undesirable liquids such as water. A sump pump is a pump used to remove water that has accumulated in water collecting sump pit, commonly found in the basement of homes. The water may enter via the perimeter drains of a basement waterproofing system, funneling into the pit or because of rain or natural ground water, if the basement is below the water table level.
The sump pump will take whatever water is right there and pump it out. The sump pump is usually placed in the lowest part of the basement so when the water comes in, it will flow across the floor to the sump pit, so the sump pump can then pump it out. The sump pump provides an automatic way to get the water out of the basement as opposed to using a Shop-Vac and having to dump it out manually.
Sump pumps may be connected to the sanitary sewer in older properties. Today this practice may be against the town’s the municipal code because it can overwhelm the municipal sewage treatment system. When a large storm produces more than an inch of rain a tremendous amount of water can be sent to the Sewage Treatment plant all at once. This is essentially clean water that should go to storm sewers to be properly diverted. Many homeowners have inherited their sump pump configurations and do not realize that the pump discharges to the sanitary sewer. If the discharge is fed to a sink in the basement it's probably going into the sewer. Municipalities urge homeowners to disconnect and reroute sump pump discharge away from sanitary sewers. Fines may be imposed for noncompliance.
The sump pump should be one part of a complete waterproofing system. A sump pump alone is not effective to lower the water table under the house and prevent water infiltration. Having a sump pump without a delivery system (such as a complete waterproofing system) can be likened to having a heart without arteries and veins; it's just not going to work right.
Even with a high quality primary sump pump, you will still need a reliable backup sump pump to minimize your basement flooding potential. Sometimes a storm will cause power outages. The sump pump in your basement is powered by electricity. If the electricity goes out, even for a relatively short time like an hour, a significant amount of water can enter your home. An hour of water entering your basement can cause thousands of dollars of damage.
Most people have heard of battery back-up sump pumps. Most people have not heard of water powered back-up sump pumps. Let’s address the question; which is better; water powered backup system or a battery powered backup system? The vast majority of battery back-up sump pumps have a battery pumping time of less than 12 hours. Trees fall and power lines are down, it can take up to a week to restore power to all homes. Water powered emergency pumps will run as long as there is adequate municipal water pressure, typically greater than 20 PSI.
Years of professional experience with primary and backup basement sump pump systems leads to the following conclusion: for the vast majority of homes, water powered sump pumps are the best solution.