I have seen several PVC grey water drainage systems but only on those with Colemans. I decided to make a PVC grey water system for my popup using the standard 3/4" drain connector from my popup. It was very easy to do, is cheap, and leakproof. I just thought I d share:
http://sactocampers.tripod.com/sactocamperswebpage/id17.html
SactoCampersneati sacto....emailed the link to the DH