This isn't going to be much help because I dropped my holding tanks and ripped out all my water connections and drains. I also tossed the sink, toilet and shower pan. What I found was all the connections were-press fit and prone to leak. The drain lines were styrene and also prone to crack. And this is on a Gulf Stream. Everything will replaced with marine grade fittings and flexible hoses. My system wasn't built to flex or repair.
1990/2014 30ft Gulf Stream Sun Clipper
and a couple of bikes
exit 100 NJ