NH law:
"II. ""Houseboat'' means any ship, boat, raft, float, catamaran or marine craft of any description upon or within which are located sleeping and toilet facilities, regardless of whether such facilities are of a permanent or temporary nature."
sa meredith, Skip makes a great point. If you have a porta-potti, leave it at the dock and you are good to go. "Sleeping facilities" are too easily misinterpreted, IMO, could mean a sunpad for all I know. All of the overnight mooring prohibitions plainly refer to this houseboat definition.
Oddly enough, these laws actually encourage folks to remove the toilet facilities from their boats, spend the night at anchor, and just sneak into the lake when nature calls.