Filling Fresh Water Tanks From 5gal jugs

Does your trailer have a gravity fill port or is it pressure fill only? Do you have a winterizing hose for drawing in anti-freeze? Do you need to conserve battery power so much that operating the pump is an issue?

I modified my trailer by adding a gravity fill port and connected the winterizing hose to the city water fill line. Now I can fill by pouring in from a jug, pressure fill from city water, draw water in thru the city water connection, use water directly from an external container and doing any of this without using the filthy winterizing hose or letting filth in from the tank vent.

Yes on my 5th wheel water control valves,  it can be set it to "winterize"  so you can siphon antifreeze into the lines and bypasses the fresh water tank.

There is another setting on mine labeled "Fill/Sanitize fresh water tank.  I can use this setting to siphon water from a five gallon jug to my fresh water tank using the on-board water pump.

Or as stated below you can purchase a "Transfer Pump" and pump it into your city inlet.  Harbor Freight sells a 12 volt version that connects to a battery with alligator clips for about $50.00. 
Rick