Filling fresh water tank before trip, good or bad?

Does the NP have a place to hook up to get water?
Federal parks do not like you to connect a hose to their water spigots as they are afraid of contamination.
Usually it is ok but if you get a strict enforcement type you could be hauling water when you get to the park.

Besides the water from your house is better on your digestive system providing you have sanitized the tank and plumbing