Check Valve location

[Photonica]

An employee at a store said I could put the check valve after the spin-down sediment filter, such as: supply>spin-down sediment filter>check valve.
That would put a negative pressure load on the filter when the pump is not running. Am I correct in this thought?

 

[Cacher_Chick]

You have not told us anything about your system. Why do you think you need a check valve?

 

[Sponsor]

 

[LLigetfa]

A check valve above ground (unless part of an airmaker) is illegal in many states and a bad idea in all states.