Re: Stupid Question From a New Owner
Definitely sounds like you have a grey water tank. I think the standard configuration would put it in the galley cabinet under the sink, but as others have said, it could be mounted under the van. TO make it a little more complicated, there is no real standard size for a grey water tank. Ours is small and is located in a little nook between the body and the end of the suspension.
I would look for the end of the drain line, which should have a screw on cap and likely a gate valve of some sort, and then track back to find the tank.
Greg in Austin
2008 Ford 6.0PSD EB/E-PH SMB 4X4 Aluminess f/r bumpers (13.5mpg avg, 15mpg hwy) 52k miles [Texas McBeast]
2006 Toyota Prius (48 to 68 mpg) 120k miles [Penelope]
2013 Jeep Wrangler Unlimited Rubicon (15 to 18 mpg) [Johnnie]
2012 Mitsubishi MiEV (no gas required) ($.50/day in electricity) [Evie]