We use the white hose that came with the startup kit (extra) for our new 2514G. Now into 7th week of trip from Montreal to Vancouver Island, and headed home. Once I flushed and sanitized the water system - reservoir, water tank and piping, I made sure to only fill up and use only potable water. At places where there was no water hook up, I used our 2 gallon flexible water carrier and hauled from tap to trailer. We drink the trailer tapwater so I don't want the system contaminated.
Yesterday, we left the Kananaskis for Calgary West Campground. Called ahead to reserve. Upon arrival there was a boil water advisory in effect, just for the campground that uses city water. Fortunately, we still have some water in the tank. The campground could have warned me and I would have come in with a full tank. Some other campers, mostly trailers, are ignoring the advisory and are connected to the water system. I prefer to stay on the safe side.
I have a WaterPur CCI-5-Ca filter cartridge in the system that helps filter and protect from contaminants (not all, I presume) the water entering the system from both the tank and external. I followed the instructions for sanitizing prior to installing the filter. If you use one of these, remember that the water source still has to be micro-biologically safe. Even with the filter, we have had bad-tasting water at at least one campground. I thought that the filter had gone bad, but the water ( and the coffee) tasted fine at the next campground.
Lastly, try carefully to make sure that your water hose does not get contaminated. I carefully drain mine after each use (site) and I connect the ends together. I also flush the hose before connecting to the trailer and I try to have it full or almost in order to limit the amount of air entering the system.