Fresh water tank valve, open or closed

[dhinkle57]

Still new and learning. De-winterized over the week end. The dealer left the valve to to fresh water tank closed, so I opened it to use the water tank and pump to flush the system. Most of the sites we use have city water so should I leave the valve open or shut it?

[norty1]

I would close it and put 5 gallons in it for flushing on the road.