The bigger problem is that when folks wash their dishes, hair, teeth at one spigot, all that******is going in one place. When we volunteered at a national park, one of our duties was to dig out those spigot areas 1' deep and replace with new drainage material. You would not believe the goop in the previous material. Disgusting. The problem was, water was not draining properly and the areas were one big puddle constantly...and yet people washed their dishes in that mess.
Another time, in a different park that had the outside sinks with a sign above it "for washing dishes only". One guy emptied his porta potty into it and the same week a man, not a kid, got into the tub to take his bath!
To the OP, yes, you should have mentioned this to the host. That's what they're there for - to clue in some very inconsiderate campers! Believe me, we've seen it all, and more....