Water pump

Old Biscuit is exactly right
.
At one place we stay I keep water in the tank and turn the pump on when I take a shower. The park water is from a well and the pressure is only about 30 psi and drops to 20 psi or so when a lot of people are using water. The pump cycles on when the park water pressure drops and off when it comes back up.

BOB Elwoood wrote:
I'm brand new. Do you run the pump when hooked up to pressurized water supply?

No - that's why your hooked up to the water supply.

The water pump discharge and the 'city water' connection BOTH feed the same plumbing system.

Depending on which one has higher pressure will determine which source feeds system IF using both.
Water pump has an internal check valve to prevent 'city water' source to backfeed thru pump and vice versa 'city water' connection has a check valve to prevent water pump to feed thru connection.

Typical standard rv water pump has discharge pressure of 45-55 psi.
'City water' sources can have various pressures.......30 to over 100 psi depending on source. Because of the various pressures that can be found it is a 'safe' idea to use a pressure regulator when connected to 'city water' source.......Watts makes a several good adjustable ones.
Ours is set for 50 psi (static)

It is impossible for the water pump to draw on the pressurized water supply if the check valve is working propery. The pump pressure will close the check valve and all you are getting in the water pump pressure.

Most will not run when hooked up since the system is already pressurized. I know if I'm hooked up to a water supply my pump will not run.

There is no need to but some do and say it increases water pressure. I prefer not to and not hear it run. There is no harm in doing so.