have a 1983 pace arrow class A, My question is....My water pump comes on periodically about every 3 minutes and runs for about 5 seconds. All this is going at anytime when I turn my water pump switch on to wash my hands etc. I don't see any leaks any where where I can see my plumbing and also noticed that My holding tank from the sink water can be emptied and with out using any water after the fact I can let it sit for a while and open the valve again and it will have water to drain out. Any ideas on my problem? Any input will be greatly appreciated.