HOW DOES A SUMP PUMP WORK? It’s Easy If You Do It Smart

You have probably heard a few details on what a sump pump is but have never quite understood the nitty gritty behind what it is for and how it works. Before we delve into the details, it is vital to know what a sump pump is and what it is used for.

To put it quite simply, a sump pump is a tiny pump that is installed in the lowest part of a basement or crawlspace. The main purpose of a sump pump is to help keep the place under the building dry. In addition, it also helps prevent flooding and heavy plumbing damage.

You may be asking yourself, “Do I really need a sump pump?” Well, the answer is this. If you live in an area where is prone to flooding, this equipment is a must have for you. In this article, we will seek to talk about how the sump pump works in performing its main function.

Types of Sump Pumps

Sump pumps are made up of many components and come in different styles. If you are thinking of purchasing one, the first thing to know is the different types. They include:

Pedestal Pumps

This is one of the most common types. Inside a pedestal stump, is a motor mounted on a small pedestal. The entire unit stands about 30 inches tall. With this type, the impeller is placed at the bottom of the sump pit while the motor is above the pit and up in the air. This contributes to the loudness of the pump.

Submersible Pumps

This is a smaller unit compared to the pedestal pump as it stands at about 12 inches tall. As the name suggests, it submerges and sits in the bottom of your sump pit. Plus, it is a fully contained electric pump. Unlike the pedestal pump, the submersible pumps do not have an intake pipe that sucks up the water that is to be sent out. Instead, the pump is located right at the bottom of the unit. The water is actually sucked right up through the bottom of the pump.

Ejector Pumps

This type of pump has an application that will allow it to eject some small debris. Also, if you have a crawlspace that is made of gravel and not concrete, this sump pump is your surest bet. Granted that it may be more expensive than other sump pumps, it does definitely give you the worth of its money.

Sewage Pumps

This mostly applies to older homes where the sewage is not handled by the city council and all of the wastewater in the house is funneled into the sump pit. This means that all of your dishwater, shower water, washing machine drainage, and even the toilet flow directly into the bottom of the sump pit. In such a case, you would need a sewage pump to deal with this situation.

How a Sump Pump Works

So basically, a sump pump consists of four major parts namely:

  • A groundwater collection system
  • A sump tank
  • A pump
  • An outlet drain

Ground Water is collected

Groundwater is collected by drain rock and drain tile that is buried along the foundation. The water is carried to the sump tank through the drain tile. This sump tank is mostly buried in the basement floor. The sump tank, which is also called a basin, crock or sump pit, can be made of either clay, tile, steel, concrete, fiberglass or polyethylene.

Sump Pump Turns on

As the sump tank or sump pit fills with water, the pump automatically turns on. It moves the liquid, mostly water, out of the pit through pipes that run out from your home to an area where the water can drain away from your foundation. The thing here is to keep your foundation dry to prevent any structural damages of the basement or house in general.

The pipe has a one-way valve known as the check valve which is located at the pump end. The main function of this check valve is to keep the water from flowing back into the pit. 

Float Activator and Pressure Sensor

An automatic sump pump turns on through what is called a float activator arm or a pressure sensor. What the pressure sensor does is that it exerts more pressure on the sensor than air does. This, in turn, causes the pump to activate.

On the other hand, when you think about the float activator, think about the one in your toilet tank. A buoyant ball floats on top of the water, manually moving the arm as the water level rises.

Movement of Water

Most home sump pumps use a centrifugal pump to direct water away. When the pump is switched on, the motor, in turn, goes on. This causes a fanlike device known as an impeller to turn. Centrifugal force definitely plays a role here when the spinning impeller forces water to the sides of the pipe.

Here, it creates a low-pressure area at its center. Thereafter, water from the sump tank rushes to fill the void, thus causing the impeller’s action to push water out through the pipe.

It is advisable to buy an automatic pump because of the convenience that it grants you. You do not have to keep turning it on. Additionally, the automatic type also has an option of activating the pump if the float arm or sensor fails.


So if you have been wondering how the sump pump manages to prevent flooding during the rainy season or when the snow melts, there you have it. It is a very important device because in the long run, it saves you a lot of trouble.

However, it is important to remember that the sump pump is always in or near the water. Therefore, it is a good idea to ensure that you have a-Grounded Fault Circuit Interrupter (GFCI) on the outlet as a safety measure. This helps prevent major accidents such as electrocution.

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