Backflow Preventer vs Check Valve: What’s the difference?

By | November 11, 2016

Backflow preventer vs check valve. Why? Aren’t they the same thing? For years, people have been using the check valve for the purposes that are supposed to be fulfilled by a backflow preventer. However, times have changed and with all the chemicals and contaminants, both residential owners and land developers have opted backflow preventers. The health hazards are very real and the last thing you want is to acquire diseases from foreign substances that are possibly floating around in your water. However, this doesn’t mean that you should stop using check valves, they can still be useful. If you want to know the difference between backflow preventer and check valve, read on and find out for yourself.


Backflow is the reversal flow of liquid, gas, or solid in a more fluid medium that is not an intended consequence of the design plan.

Back siphonage is the reduction of pressure causing substances to move from an area with high pressure fluids to one with low pressure fluids. Put simply, this is when fluids are removed from the system.

Back pressure is the opposite of back siphonage. It is the movement of undesirable substances from an area with low pressure fluids to that with high pressure fluids, the pushing of substances to the system.

Cracking pressure is usually indicated by bubbles and is the first sign of the presence of flow.

Reseal pressure, the opposite of cracking pressure, is the pressure that shows no indication of flow.

Backflow Preventer vs Check Valve

A backflow preventer is a device that does just what the name suggests: it prevents backflow by reversing the effects of back siphonage and back pressure. There are different types of it which you can purchase from Wilkins backflow and install, depending on your purposes.

A check valve, also known as non-way valve, only allows the flow of fluid in one direction. Thus, it merely controls the flow. It has two openings, one designed for the entrance of water, and one for leaving.

Both devices are meant to totally prevent the reversal of water flow. However, a backflow preventer, although still having a relatively simple design, undoubtedly has a more complicated mechanism. It consists of more than two openings. Therefore, in the match of backflow preventer vs check valve, the former definitely wins. With its more intricate system in impeding the passage of any hazardous substance, it is more the more viable option for protecting your water supply.

What is the only certain way to prevent backflow?

Truthfully, both devices are able to prevent backflow. The biggest difference between backflow preventer and check valve affecting you decision, however, is the ability to protect you from hazardous wastes. Needless to say, the latter cannot be used unless you’re sure about how safe the water source is. Moreover, to comply with the regulations and building codes, you better install the former.

Knowing the advantages of using backflow preventer vs check valve, it is only wise to go with the one that gives you a sense of security. With Wilkins backflow preventer, there is always a viable option for your needs.