Is It Possible To Restrict The Flow Of Water In One Direction?

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It is possible to restrict water in one direction using a check valve. This type of valve uses materials such as balls and discs to control the water flow. It is also used to prevent backflow and maintain the flow of water in one direction.

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Does water flow in one direction only?

The urban legend says that the water in the toilet and sink flows differently in the northern hemisphere and southern hemisphere. They either flow in a clockwise and counterclockwise direction. People believe that it happens because of the Coriolis Effect. But that is true for hurricanes and typhoons because of the large amount of water in the ocean. Because the toilet and sink have smaller space, it doesn’t work that way. In fact, several experiments proved that the water moves the same in both hemispheres.

When it comes to the piping system, water usually flows in one direction unless there is backflow. If the valve does not work, backflow can occur.

Backflow happens when the pressure is too strong that can bring the water back to its source. Instead of moving from inlet to outlet, the water goes from outlet to inlet.

The latter movement of water does not occur in the plumbing system to avoid water contamination of potable water used.

Is it possible to restrict the flow of water in one direction?

It is possible to restrict water flow in one direction using a check valve. A check valve is a device that functions to prevent backflow in the piping system. This type of valve comes in different names such as one-way valve, non-return valve, and backflow preventer.

Restricting water flow in one direction is used in several applications. One of the most common applications is in the sewer system.

Plumbers prefer using a check valve to ensure that the wastewater won’t backflow to the clean water. It ensures that the household consumes clean water all the time.

Another application is the reverse osmosis filter. It avoids the backflow of the dissolved salts giving you freshwater. Check valves are also used on lawn sprinkler systems and hose bibbs.

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How do you make water flow only one way?

You can make water flow in one direction by understanding how the mechanism works and the types of valves available in the hardware stores.

Understanding the mechanism allows you to figure out how to assemble a check valve in the piping system and figure out why it is not working.

Before I discuss the types of check valve, let us begin on how it works. Three elements make the check valve works. It includes the cracking pressure, closing mechanism, and installation orientation.

These elements play important roles to ensure that the check valves work properly and preventing backflow.

Water flow mechanism

Cracking pressure is important as it is responsible for opening a check valve so a steady flow of water passes through the pipe and reaches the outlet port. It is measured through psi or bar.

The minimum pressure is between one psi and five psi. However, take note that the cracking pressure varies depending on the valve design and valve size.

So, make sure that you know the cracking pressure on the check valve you will use.

The closing mechanism is responsible for avoiding backflow. Backflow happens when the water that passes through the check valve directed to the outlet port goes back to the direction of the inlet port. A faulty closing mechanism can lead to backflow so this element must be built in the right structure.

Several closing mechanisms include a ball, disc, or diaphragm. These mechanisms close the opening when the backflow occurs. Similar to the cracking pressure, it also varies depending on the check valve you will use.

Before you set up the pipe and the check valve together, always check the orientation of the check valve when you install it.

Wrong orientation can lead to backflow, which is not the desired output for this project. You want to nail the installation in one time to avoid reinstalling it.

Check valve types

Now, let me continue the discussion with the check valves available in the hardware stores.

There are different types of check valves such as spring-loaded in-line, spring-loaded Y, ball, diaphragm, swing, wafer, and gate valve. The in-line type comes with a spring and disc to open and close the valve.

The valve’s design prevents pressure surge that can lead to rupturing the pipes. It also prevents water hammers that can damage equipment.

Spring-loaded in-line can be installed in two ways – vertical and horizontal. Although the mechanism works, the disadvantage of using it is during line inspection. You must remove the valve before you can proceed to a maintenance checkup.

On the other hand, the spring load Y can stay connected to the piping system during maintenance because it is designed at an angle. It works the same as the spring-loaded in-line but its size can be a disadvantage as it takes up space in the piping system.

A ball check valve works almost the same as the spring-loaded in-line but instead of a disc, it uses a ball to seal the reverse flow. It seals tighter than the other types of valves as it creates maximum contact area.

It is durable and can withstand dirt and harsh environments. However, if you want a fine flow control, this type of valve is not suitable. It is best to use for shut-off applications.

The diaphragm check valve is composed of an inlet port and outlet port. In-between these ports are the diaphragm. It is a close valve and it is considered a two-way valve.

The diaphragm opens up when it receives water pressure and it opens for full flow on increased pressure. It closes when backpressure occurs.

However, this type of check valve is only applicable to low-pressure vacuums. It flies out when it receives high pressure.

The swing check valve parts include gasket, seat, disc, bonnet, and body. The bonnet allows easy access to the valve. The gasket is softer than other components and it gets squeezed between the bonnet and the body to ensure that the valve gets sealed.

The disc swings to seal and open the entry point and when it is closed it rests on the seat. It opens due to cracking pressure and it closes due to sealing pressure.

A wafer check valve is similar to a swing check valve as it has a disc to prevent backflow. However, the disc is aligned to the body and the seat. When it is open, it is positioned perpendicular to the body.

If you want a thin valve, the wafer check valve is the ideal valve to choose. It is also easy to install because of its structure. The wafer check valve is best to start, stop, and regulate the water flow. It is ideal for large water flow but at low pressure.

Gate valve is another disc type valve yet it opens and closes vertically. When you turn the knob, the disc either closes or opens the entry point.

With this structure, a gate valve is not ideal for regulating the water flow. It is only best used to allow or stop the water flow.


The piping system plays an important role in the installation of a water system in your house. Incorrect installation or wrong choice of the check valve can pose problems, particularly for your health.

Always remember that the main function of a check valve is to avoid backflow. When backflow accidentally happens in your piping system, wastewater can enter and contaminate clean water.

The check valve also helps in allowing and stopping the water flow which is suitable if you own a water tank at home.