My FIL has this problem and he can't use a pressure regulator. He is looking to see if he can find one that has a dial mechanism so he can adjust the regulator. You shouldn't be using the pump unless you are using water from the holding tank.
Number of Nights Camping - 2013 26RKS
2014 - 18, 2013 - 11, 2012 - 11
Number of Nights Camping - 2012 17Z
2012 - 10, 2011 - 13
Countless nights as kids and young adults in a pop-up, hardside TT and several tents!