What Is a Sump Pump? How a Sump Pump Removes Water

A sump pump is a cylindrical drain pump device placed in a pit dug at the lowest point of your house, like a crawl space or basement, to help prevent flooding, water damage, and mold. The device removes water from that lowest point, as well as the soil below, forcing it out and into a separate draining space. Since basements are one of the most common places for water damage, these water pumps are a helpful form of preventative maintenance against a basement flood.

To install a basement sump pump, dig a hole (also called a sump pit or sump basin) in the lowest part of your basement floor and then line it with gravel.

Sump pumps remain on standby until you need them, such as during and after heavy rain. Excess groundwater funnels toward the sump pump pit. As the pit fills with water, a float switch (or sensor floating on the water) activates when the water level gets too high, which turns on the pump. This sensor system only allows the pump to turn on when needed, which saves electricity. The sump pump system then removes the water from the pit, draining it through a discharge pipe into either a storm drain, dry well, creek, pond, or detention point, which will keep the groundwater from rising and prevent a flooded basement.

Sump pumps work with the water table (the level at which water exists when digging straight down) beneath your house. Rain causes the water table to rise. Some pumps can even detect water in the soil, draining the water out of the soil before it becomes a problem.

There are two main types of primary sump pumps homeowners can consider, in addition to a two-battery backup system.

1. 1. Submersible sump pumps: You can find the pump’s motor and housing inside of the hold. These pumps are quieter and more powerful than their pedestal counterparts, making it more ideal for those who spend a lot of time in their basement or those who know their pump will need to extract a lot of water.
2. 2. Pedestal sump pumps: The pump’s motor is next to the basin in this type of sump pump. Since this method can be louder than its submersible counterpart, this type is best for those who don’t spend too much time in their basement or whose pit is simply too narrow or deep for a submersible pump.
3. 3. Battery-operated backup: If the electricity goes out during a storm or natural disaster—which might cause your pump to fail—a pump with a battery backup can help prevent flooding while the electricity is out.
4. 4. Water-powered backup: A water-powered backup system is useful in a power outage and uses increased water pressure to clear the water in the basin, meaning there is no need to monitor or replace batteries.

There are indicators to look out for—and listen for—when considering whether to replace your sump pump, such as the equipment’s age, level of corrosion, cycling pattern, and the sound the motor produces. In general, you should replace sump pumps every seven to 10 years, with the lifespan of your pump determined by the frequency of use, the runtime of the cycles (when it starts pumping out water and then stops once the level is low enough), and the volume of water it’s had to displace.

A sump pump that runs continuously might indicate that issues with the float switch (the water level sensor) could cause a strain on the pump’s motor and lead to potential failure. If your pump takes too long to empty the basin, especially during a normal rainfall, this could indicate that your pump doesn’t have the necessary horsepower to complete its job.

Toward the end of your pump’s lifecycle, you may start to hear a roaring sound from the motor. If you can hear the rattling or clanging of your pump upstairs in your house, it’s a sign the motor is nearing failure. Loud noise may also indicate damage or improper sump pump installation of discharge lines. You may want to seek out a second opinion from a plumber.

Here are characteristics to take into consideration when you’re in the market to buy a sump pump:

• Cost: A sump pump alone can cost between $100 and $400, depending on the horsepower and flow rate, and it can cost up to $1,000 for commercial use pumps.
• Horsepower: Average household sump pumps have a water removal rate of 1,800 to 2,200 gallons per hour. Common motor sizes include ¼ horsepower (also abbreviated as HP), ⅓ HP, ½ HP, ¾ HP, and 1 HP. If you live in an area prone to flooding, you may want to consider a sump pump bigger in size and horsepower, such as one with ½ HP that can expel as many as 5,000 gallons per hour.
• Switch: A diaphragm switch is common since it rarely gets stuck on or off and operates much like your own diaphragm—moving from concave when the pressure rises and back when it lowers. A pressure switch triggers the pump once the water pressure reaches a certain level. A float switch sits on top of the water and turns on the pump as the water level rises. Finally, an electronic switch depends on probes to sense the water pressure in the basin.
• Water alarm: In addition to a battery backup sump pump, you may want to purchase a water alarm to help prevent basement flooding. These alarms monitor the level of the water and alert you if your pump fails and the water level gets too high.

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