Another consideration, although it probably does not apply to many campgrounds, is the ability to dump gray water but not black water. As an example, Borne Scenic Park, along the Cape Cod Canal, has some electric and water sites that allows one to dump gray water using a drain cap with a 3/4 inch hose fitting. The other end of the hose just fits into the gray water dump. Check out "Camping at Borne Scenic Park" in this link:
https://bournescenicpark.com/about-u...ities/camping/
Dick