Water for electric only locations

We are looking at staying at more state parks which have electric only sites. We have only been using full hook up location and want save some costs. We don't want to haul water from home or back enough bottle water for washing etc. So the question is what water access is there to fill the water tanks at these parks, in general? Do you just pull up to any spigot, is there water access at the entrance?

Just beginner