Fresh water use

[oldtrojan66]

I have noticed that I can have a full fresh water tank (65 gal in my JAYCO 36RLTS) when I pull into a site with water available. When I hook up to this “city water”, after some period of time the water in my holding tank is gone. Is this a siphon issue, or is it supposed to be that way? I have separate valves to open or close for “city water”, “city water fill”, “normal”, “winterize”, etc.
Thanks for the help!
David

[Ron3rd]

Your condition is not normal. So "No" is the answer to your question.

[wa8yxm]

IF you use a water regulator the pump may kick in to supplement
In some parks again the pressure in the city line may be less than the pump pressure

You may also have a leak

This is in addition to the above comments Turn pump off when hooked to city and see what happens,

[STBRetired]

Did you turn the pump switch off? If the city water pressure is less than the "on" pressure for the pump, the pump will run and deplete your onboard tank. Do you hear the pump running when you open a faucet?

[enblethen]

Valves are in the wrong position. Check owners manual. Label in compartment should show correct valve positon for city water usage.

[jaycocamprs]

If I understand your post, the NO it should not do that. And I don't understand how it is happening unless the pump is on, and is running as you use water. Or you have a leak.