Grey Tank - Black Tank Combination

When dry camping, I almost always end up with a full grey water tank and an almost empty black water tank. Especially when I can get more water while I am parked.

At OSH we had the honey wagon come by and pump the tanks out, but if I could have transferred some of the grey water to the black water tank, I could have probably made it a couple of more days and not had to wait around for the truck.

However, when the truck came, the honey wagon man just reached down and spun the discharge outlet to the side and hooked it up. I didn't realize you could move it. In fact, the guy said most of them are rigged up to be moved.

So fast forward to the time at which Mike, Tom, Brent and I have the hose stretched out from the water well to fill up the coaches. Mike has a short hose (6") that has a valve in it. After looking at that hose, I got to thinking, since my sewer outlet has a cap that has a water hose connection / cap on it, why couldn't I just install the short hose with the little valve on the cap and then open both tanks up and let them crossfeed. Then when it was done, I could close one side and hook water up to the short hose and flush the "WYE" out with clean water, then switch sides and flush the other side out then close it and drain the remaining semi clean water out before hooking up my sewer hose and draining the whole load.

Does this seem workable or has anyone else done it or did you figure an alternative method to crossfeed them without having that little bit of honey trapped between the two valves and the discharge cap?

When I used to own RV Crossing, Ltd, my RV business, I often picked up little tricks like this from customers. A lot of what happens on a Prevost is going to depend on the level of the two tanks. Most of the stuff I sold and serviced was travel trailers and 5th wheels so both the tanks were just above ground level, more like gas tanks on an older car.

1st you must have a termination cap with a garden hose attachment. Then you need a simple, easy-to-find hose shutoff which can be attached to the cap. After making the transfer and BEFORE removing the termination cap use a sewer-designated garden hose to transfer the liquid trapped inside to the next dump you encounter. It can also be drained into a container and flushed down a toilet, even the one on the bus. Now when your remove the large termination cap you may get a few dribbles but most likely not any more than can be cleaned up with a paper towel. Simple and clean.

Jerry, I just read your post a little more carefully and find that my post was a repeat of what you wrote. Dumb!! Anyway, it does work if the Black water level is the same or lower than the gray water.

Those of you with masserater pumps how do you flush your hose when done?

Couldn't you transfer to the gray tank with one?

Now that I think about it I am going to have to get a locking cap for the fresh water tank:eek: