Here's your sign...

Second Chance wrote:
Me: having lunch in our rig watching our next door neighbor in Dolphin class A pack up to leave (20 minutes after check-out time). Observe man disconnecting fresh water supply hose and, with bare hands, putting it about five feet down the stinky slinky to rinse out the sewer hose. I step outside - "Sir, is that your fresh water hose you're putting down the sewer hose?"

Him: "Probably."

Me: "You'll need to throw that away now to avoid serious infections."...

That's the point were I would of grabbed the hose and took a big long drink of water out of the end of it and then offered the OP a drink. People that work in the wastewater industry would understand. The OP would have turned green and ran back in his camper with his sign, which is where he should have stayed.