Plugged Drain

If you're super picky about never putting any kind of dish washing water, grease, etc. down sink drain there shouldn't be a clog. If you use it be real careful with the Draino and really rinse well after. I keep a wire drain screen in all sinks to prevent anyone from inadvertently dropping something down the drain. When we were testing things at our son's house where we bought the camper water came up in the shower pan too. Duh, we didn't read the little note previous owners left that said to always open the drain cap below the black water gate valve or it would back up.....no on board grey water tank! LOL live and learn. Blue boy tank a constant companion now as no space to add a grey tank on our old unit.