Pressure Tank not holding water
With a new pump it should be good but they ( the check valve) do get stuck sometimes. When this happens I will add a check valve just prior to the tank. Adding a valve is easier than pulling the pump. I did have a line from the pump to the tank that cracked, I tried the check valve and it did work for a while but the crack got so bad it would not pump more than 20 psi, at that point we pulled the pump and found the crack and replaced the line, hope that helps.