Out of Sight but Important: Sump Pumps


A sump pump is a part of a full system of flooding protection for basements. In itself, a sump pump will assist in keeping a basement dry, especially if a part of the basement is below the water table. When coupled with a backflow prevention valve, a sump pump will give greatly increased security and dryness.

Backflow preventers and sump pumps address different (though potentially related) causes of flooding. Backflow prevention will stop water rising up from beneath the basement floor through the sewer system; a sump pump will assist a basement’s weeping tile system in preventing water entry through a building’s foundation, although a sump pump might also help with more general basement flooding (However, in that case a problem already exists).

What is a sump pump?

A sump pump is a pump designed to remove water from a “sump pit” located below a basement’s floor. The water, collected in the sump pit from weeping tiles outside the basement wall, is then pumped out through a discharge pipe and sent away from the basement, often outside the wall of the basement far enough that it poses no risk of re-entry. The simplified diagram below shows a basic sump pump installation.


A sump pump is a part of a system, in fact, consisting of a pump, a pit, and a pipe. The sump pit is a plastic or metal lined basin built into the basement floor, typically a couple of feet (0.6 m) across and two or three feet (0.6 to 1 m) deep. The sump pit holds the sump pump, which is either fully submersible or of a pediestal design (where the motor is located about the water level of the sump pit, and the impeller sits at the bottom of the pit).


The sump pump is usually automatically activated by a switch that detects a rise in the water level in the pit, often using a flow switch or other sensor. When the water level in the sump pit is high enough the pump is activated and the water in the pit is pumped through a pipe to the outside. This design means that the pump’s operation is intermittent, saving wear and tear on the pump motor and impeller, and minimizing noise.

A sump pump system, although out of sight, cannot be ignored or it will fail at the time it is most needed. Maintenance involves checking the pump is still operational (adding water to the sump pit should initiate pumping), and making sure the pump system is free of debris and grit.

Reliability is important, and because a sump pump is likely to be most needed during a storm when electricity might be interrupted, it is good practice to also have a battery backup to ensure the pump will operative during a power outage. A back flow preventer on the sump pump’s discharge pipe can also reduce strain on the pump itself.

The City of Toronto has recognized the importance of flooding protection and provides homeowners with a subsidy to assist with the cost of sump pump installation by qualified installers such as Master Drain. The program applies to homes built before January 1, 2009 and the City will pay 80% of the invoiced cost of a sump pump installation, up to $1750, including labour, materials, and taxes. This is a great deal. Details on the program are at the City’s web site.

For the important protection that a sump pump can offer, Contact MasterDrain Drain today for more information.