Ray,

I hope my answer applies, but since I don't have your coach it could be off. My Discovery has a valve that switches the fresh water from the water source to either fill the water tank, or supply water to the coach. Most of the water centers also offer a separate input point where you can attach a hose to supply city water if you don't want to use your reel for some reason, say it was damaged. There is also a connection point for supplying city water to backflush your black tank. You will also find a fresh water fill point, generally in the same bay as the rest of the water that is about a 1.5 inch cap that you can fill the tank from. if filling from the previously mentions path using the valve, it is suggested to open that cap to allow air to escape and avoid presurizing your tank.

Hope this helps.