A few years ago, I had asked DW if everything was switched off before we put the rig into storage. She said yes, and I wasn't dumb enough to check it. I also didn't have a battery cut off wired in.
Well, you can tell what happened, I opened my drain valve, drained out all my water, and then put the rig in storage.
I was in a hurry and forgot the keys to give it a once over. Unfortunately, the water pump wasn't switched off and something caused the line to be unpressurized and well, the pump started running.
It ran until one two of my Golf Cart 6 volt batteries were dead (I mean dead, as in a door knob).
Now when I run the pump, I get pulsation from the taps on the sinks - but not all the time. Just some of the time. An expansion tank would fix the problem, but I have other projects and not enough time to get to all of them.
Just my experience. I don't know what happened that's caused the pump to pulsate, but I do know an expansion tank would solve the problem.