Originally Posted by Ray,IN
Just to understand; do you mean you're using your onboard water pump while attached to city water pressure?
I wondered the same thing, but didn't ask. When on city water, the line pressure should be plenty and the pump should be off. Pump is only used when not hooked up to a pressurized hose. Also, some systems have a valve that must be set from water tank to city water, you do not want to pressurize or overfill the water tank, it can bulge and cause structural damage or even burst.