A foot valve is a check valve that only allows flow in one direction. A foot valve is used where a pump is required, such as when water needs to be drawn from an underground well. The foot valve keeps the pump on, allowing water to flow in but not allowing it to flow back, making it ideal for use in pools, ponds and wells.

How the foot valve works
As a valve that allows only one-way flow, the foot valve opens one-way and closes when the flow is in the opposite direction. This means that in applications such as wells, water can only be extracted from the well. Any water left in the pipe is not allowed to flow back through the valve to the well. Let’s take a closer look at this process.

In shallow groundwater wells, the application of foot valves involves the following:

First, consider the position of the foot valve. It is installed at the collection end of the pipe (the end in the well through which water is extracted). It is located near the bottom of the well.
When the pump is running, suction is created, drawing water through the pipe. Due to the pressure of the incoming water, the bottom valve opens when the water flows upwards.
When the pump is turned off, the upward pressure stops. When this happens, gravity will act on the water left in the pipe, trying to move it down back into the well. However, a foot valve prevents this from happening.
The weight of the water in the pipe pushes the bottom valve down. Because the bottom valve is one-way, it does not open downward. Instead, pressure from the water closes the valve tightly, preventing any backflow back into the well and from the pump back to the sump.
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Why do you need a foot valve?
Foot valves are beneficial as they prevent possible damage to the pump due to idling and stop energy wasting.

These valves are an essential part of any pumping system. The above example explains how the foot valve works on a very small scale. Consider the impact of not using a foot valve in larger, higher capacity situations.

In the case of pumping water from a ground sump to a tank on top of a building, it is necessary to use a powerful electric pump. As with the examples, these pumps generally work by creating suction that forces water up through the plumbing to the desired tank.

When the pump is running, there is a constant water column in the pipe due to the suction generated. But when the pump is turned off, the suction is gone and gravity affects the water column. If the foot valve is not installed, the water will flow down the pipe and return to its original source. The pipes will be devoid of water, but filled with air.

Then, when the pump is turned back on, the air in the pipe blocks the flow of water, and even if the pump is on, the water won’t flow through the pipe. When this happens, it can cause idling and, if not addressed quickly, can damage the pump.

The bottom valve effectively solves this problem. When the pump is off, it does not allow any backflow of water. The pump remains ready for the next use.

The purpose of the foot valve
A foot valve is a check valve used with a pump. They are used in a variety of different situations around the home as well as in some industrial applications. Foot valves can be used with pumps that pump liquids (called hydraulic pumps) (such as water) or industrial applications (such as gases) (called pneumatic pumps).

At home, foot valves are used in ponds, pools, wells, and anywhere else that has a pump. In industrial settings, these valves are used in sewage pumps, air intake pumps used in rivers and lakes, air brake lines for commercial trucks, and other applications where pumps are used. They work just as well in an industrial setting as they do in a backyard pond.

The foot valve is designed to keep the pump primed, allowing fluid to flow in, but not out. There are strainers that cover the valve opening and can clog after a while – especially if they are used to extract water from a well or pond. Therefore, it is important to regularly clean the valve to keep it operating efficiently.

Select the right foot valve
side brass foot valve

A foot valve is required in many cases. Anytime there is an application that requires unidirectional liquid flow, a foot valve is required. A quality foot valve helps save energy and protect the pump from damage, extending its overall lifespan. Remember that it is important to use the best quality foot valve possible, as they can be difficult to access once installed.