Gray water, pumps, etc

[Suz]

Since I don't have a gray water tank, I use my blue tote when camping. I have no problems with it since it's just me and it is easy to empty (I use a ten gallon). However, there are times when it would be nice to have a small built-in for quick overnights and rest stops. The newer (than my) Casitas have one located beneath the trailer toward the front, so this allows them to be gravity fed even for the shower. However, I believe the Scamps use a small pump to move the gray water into the tank. I assume this is a small "on demand" style pump. Thinking that this would certainly leave me more options in placement of my tank, my thoughts turned to something else.

I began to wonder the feasibility of a larger gray tank located inside the back of my SUV (truck would be better, but I don't have one right now.) If it would work, then there would be zero lifting involved and would allow me to have a much larger tank. When it came to empty it, the larger four-wheelers already have a side discharge so I could just pull it to the edge connect the hose and let her rip.

As I said, this is just for gray and since that is where I carry my blue tote anyway, why wouldn't it work? I have a 12V outlet in the back of my SUV that could run the pump, so whaddaya think?

[Brian B-P]

I think this is an interesting approach, treating the tug as a "tender" (in boating terms) to provide any required support to the trailer. I agree that a pickup would fit this particular duty better (and could do black water as well as grey), but the SUV (or van) would work for greywater, and conversely for bringing fresh water (in a separate tank!) as a tanker to refill the trailer supply. I suppose one could support indefinite use of the trailer in an unserviced location (boondocking) without having to move it, using this approach.

I think the transfer pump is better located in the trailer (under the floor near the shower) so that it would not need to pull uphill on the suction side. Not having the pump in the tug means not having it available for emptying the transfer tank, but Suz was planning that as a gravity operation anyway.

To avoid excessive rear axle load, I assume that anyone planning this on a large scale (large tanks) would always empty the tank(s) before hitching up. The importance of this would depend on the specific tug, trailer, and tank.

An alternative implementation could carry the tank on a hitch-mounted cargo platform, which would have to be removed (and carried on a roof rack, for instance) to hook up the trailer. This method could even handle black water (since it would never be in the interior), but would be limited in size by hitch load capacity.

My only significant reservation would be that if the tug-carried tank is the only tank reachable by the shower, not just for transfering from a trailer-mounted tank to the dump site, then the tug must be present and hookup up (by hose) whenever the shower is to be used. I assume that there would still be a small tank for the sink, for this reason.

[Benny K]

Interesting concept but I don`t think that having the pump in the trailer and tank in the truck would work too well....where would the disconnect be? ....don`t forget that you are pumping uphill from the bottom of the trailer to the top of the tank in the truck bed and once the pump runs out of material to pump it`ll just run partially empty and cavitate without pushing anything beyond the pump to the storage tanks....check valve right after the pump would be fine but the disconnect would have to be there also and with grey or heaven forbid black water you would have leakage of some amount all over the ground every time you disconnect......the solution would be a vacuum pump like a septic tank truck but you`d possibly still have some leakage.....when your vacuum pump empties the line it`ll be empty all the way to your tank......another possibility is to put a rise in the line that`s higher than the top of the tank and locate your valves and disconnect there...disconnecting at top of the tank would still leave a lot of waste water in the line......this is getting pretty complex and messy.......I`d mount the tanks under the trailer like where they usually are.....Benny

[Brian B-P]

Benny has an interesting point about the remaining waste water in the transfer line. I would consider a dry-break coupling at the trailer end of the hose, and just lift the hose up to drain the last bit into the tug-mounted tank. The common plastic or brass quick-connect garden hose fitings (which just screw on to the normal hose threads) are available cheaply in a version which shuts off like this, but I don't know if they would be flow freely enough and shut off tightly enough when used with waste water (which would have some debris in it).