QUOTE(John S. @ Aug 20 2009, 05:49 AM)

Dave you are right on Monaco not using a single tank but I have seen it in bus conversions and truck conversions as well. I have been told it works better though I have two tanks. I understand about filling and backing up into the shower as well.... Not a pleasant picture or site or smell.
If you are boondocking though and recycling grey water or boondocking and your single tank is bigger than your water supply as is the case then this should not happen.I fear it would happen when you are hooked up only.
Good point, John, but it depends on how you boondock.
We have spent months at a time boondocking in Quartzsite. I have a 30 gallon "Water Boy" fresh water bag with an attached 12 VDC pump. When I go in to town, I fill that up in the back of the Explorer (toad), so we have unlimited fresh water.
We dump our dish water down the toilet if it isn't too greasy.I also have a 10-gallon blue boy that I use for gray water. I can lift that 85 pound thing into the back of the Explorer to take to the dump station. Every 7-10 days I call a honey wagon and have both tanks pumped. We let both tanks fill up before we call them.
Our favorite honey wagon in Quartzsite is "The Duck." His motto is "The Duck Sucks for Twenty Bucks."