Check Valve vs Foot Valve for Pressure Pumps

An essential part of the plumbing set-up for a pressure pump is plumbing a one way valve on the inlet side of the pump. This helps the pump to maintain prime from the inlet and is necessary both if you’re plumbing directly from a tank (i.e. with positive pressure pushing into the pump inlet) and especially with a suction set-up. Suction set-ups especially must have a one way valve, as without the one way valve, the pump can never maintain prime and will not work. 

Now not just any old one way valve with work. There are 3 main types of one way valve, a swing valve, a check valve, and a foot valve.

 A swing valve, like its name suggests, has a small swinging “gate” that allows the water to flow one way, but when the water pushes back the opposite way, will shut and stop the water from back flowing.

A check valve is a spring loaded valve that also allows water in only one direction, but due to the spring, it is much better at holding pressure.

A foot valve is the exact same as a check valve, just with the addition of a metal sieve-like mesh to keep debris from flowing into the line. 

A swing valve does not have the best seal, so it’s not recommended for this set-up. A check valve is better, but still not recommended for this set-up as it allows for debris to get caught in the valve.

We've had a very unfortunate (and slightly humorous) call from a customer whose pump was not holding a prime despite having a one way valve and positive pressure. We discovered he had used a check valve on the water from his pond, feeding to his pump and a fish had swam into the check valve and gotten stuck. Thereby keeping it stuck open. This story outlines exactly why we only recommend using a foot valve, as that metal filter can protect from situations like this.