Originally Posted by OldCoot
Keeping the grey valve open is venting the entire campground sewer system thru your camper and it is really not designed to handle it.
Keep all holding tanks closed until 2/3 to F.
Listen to OC on this one! I have a friend whose Dad was camping for several weeks at a campground with full hookups. He left his drain valves open the whole time. After about a week he started feeling really bad and thought he was coming down with the Flu or something. After basically laying around in the camper for another week and getting worse and worse they hauled him to the hospital in an ambulance.
Come to find out he had "Gas" poisoning from the level of toxic gas in his camper which was backing up from the campground waste system. There ended up being over a dozen other people in the campground that had been staying more than just a few days who had to be treated as well due to the toxic levels of "Gas", I assume Methane, in their blood.
Bottom line, I keep mine closed and drain when needed. It isn't too big an inconvenience to walk around to the other side of the unit and pull a couple handles when needed.