We have two points with "low point" drains, one at the fresh water tank and two on the passenger side of the cargo bay as noted by Cosmik. I got tired of taking the two screws out of the little panel, and trying to get them back in the same holes, so I just put two mirror hangers, little ones, on the bottom and one on the top. Now when I wish to take the panel off, I just swivel the upper hanger to the side and remove the panel. Now, we'll see how long that set-up lasts, although I did attach them with little bolts and nuts to see if I could make them last longer.
2012 GMC 2500HD D/A Crewcab
2012 Jayco Eagle SuperLite HT 26.5 RLS
2009 Crestliner Superhawk 1900
2013 Polaris Sportsman 550 EXP
2008 Polaris Sportsman 700 X2