knocking in check valve

when my pump is done running there is a banging noise in my check valve
i am sure it is the water pushing it closed,but what i dont no is how to fix the problem,anyone got any suggestions.thanks in advance

If this check valve is at the pressure tank, it sounds as if the one in/on the pump's outlet is leaking. The water going back into the well causes the check at the tank to slam shut and you get the noise from water hammer.

If no valve at the tank, the one in the well may be sticking slightly until it closes.

thanks for your reply,but im not sure i follow.this problem is when my sump pump is done running my check valve slams shut,is ther any solution to this,like diffrent location of the check valve or any thing.thanks

A new, good quality check valve should fix the problem.

bob...