Connecting Grey water to Black tank?

[marioandpati]

Hello!

We have a 69 Overlander and we are overjoyed!!! We picked her up about a year ago and we now have some time to get to work on her. We are thinking about rerouting the grey water plumbing into the black tank, as it only has a black tank... It looks relatively easy if we go through the vent entry. Does anyone out there have any experience with this?

Any response would be greatly appreciated!

Mario and Patti!!!!

[RUMSHIP]

It's normally not a good idea to connect the two. You will fill up the black much faster using it for gray water. Getting a blue boy waste tank is a better and safer idea.

[idroba]

I am not sure how large the black water tank is, but probably not large enough to hold much gray water in addition to the black. Also, I doubt that you can bring the shower water in as the top of the tank and vent line you are thinking of using is too high to drain the shower water into. And of course you want to be very careful about the black water backing up into low things, like the shower pan. No fun to deal with at all.

If you are going to do such a project, I would recommend a separate gray water tank be installed, rather than trying to make the black water tank do double duty.

[TG Twinkie]

My '74 Argosy has a small (12gal) grey water tank. I wanted more grey water capacity, but did not want to tear up the floor or the belly pan to increase the capacity.
I have been using a 10 gallon Blue Boy for the last 3 years. It was OK, but at times it was a bit of a hassle.
So this year I decided to install an "auxiliary" grey water tank. A second tank (21 gal) under the curb side twin bed above the axles. Now when the original tank gets full, I pump the grey water into the auxiliary tank. When they are both full (33 gal) a stop at the dump station is all that is needed.
It is less of a problem to connect the garden hose for the pump to transfer the water than it was to connect the sewer hose to the Blue Boy. And I don't have to drag the Blue Boy and sewer hose to the dump station.
The total cost of the project was about $250.00 including a relatively ($104.00) expensive pump.
It may be some what unorthodox, but it works for me.

[Jammer]

Originally Posted by marioandpati

Hello!

Welcome

We have a 69 Overlander and we are overjoyed!!! We picked her up about a year ago and we now have some time to get to work on her. We are thinking about rerouting the grey water plumbing into the black tank, as it only has a black tank... It looks relatively easy if we go through the vent entry. Does anyone out there have any experience with this?

I have a '71 Cayo and have just added a greywater tank to it.

In general, using the existing black tank as a combined holding tank isn't a workable solution for all the reasons noted upthread --- capacity, the potential for sewage backup into the shower, and the fact that the shower drain is in most cases below the top of the black tank.

While I do not have a late 60s Overlander, it is my understanding that it is reasonably straightforward to add a greywater tank between the frame rails:

Gray Water Tank

A possibility with less upfront cost and effort is to add a greywater tank to your tow vehicle and use a shower basin, bilge pump, or filterless diaphragm pump with it.

The blue totes are a possibility but really aren't workable, for most people, if you're going to use the shower, because of their weight and size. The smaller ones work OK if you're just going to use the sink.

[TG Twinkie]

My original thought was to put the GW tank in the truck. Then I thought. Why take up the space in the truck. When I can put it in the trailer. I only lost 4 cubic feet of storage, which I made up for with additional cabinets else where. The only hose I have to deal with is a 6' length. It is actually a washing machine hose. Already connected at the pump end. So it is really effortless to transfer the GW.

[xrvr]

Years ago I had a 1971? Airstream and I had a dealer connect the two drains together. It was low volume but what we needed since we used full hook ups most of the time. About ten gallons I think. Allowed us to use the toilet and sink while on the road during rest stops, and then dump and usefull hook ups when we camped. Jim

[Jim Foster]

A very bad idea for the reasons listed above.

[xrvr]

If one cannot monitor to some extent the volume going into the tanks and dump often, then perhaps one should not use the toilet and sink at all. One reason I sold my airstream is because of issues like this that prove some owners should stay home because it is too ICKY to actually camp. Jim

[TG Twinkie]

I am confused about what zigg said.
If you mean put grey water in the black tank, I agree, not a good idea.

[Kyle401]

Welcome Mario and Patti.

I also own a '69 Overlander. If your camper is still equipped with the factory original plumbing, the gray water is routed to the dump connection downstream of the black water valve. If you are going to camp without full hookups, you will need to find a solution to the gray water problem. In some parks you will not be allowed to discharge gray water which essentially limits you to dry camping and emergency bathroom use.

The easy way to use your black tank as a combo tank would be to buy a Valterra / Thetford adapter (Valterra number T05-2285) and mount a Valterra twist-on valve (Valterra number T58) downstream of the outlet. Then you can open your Thetford black tank valve and grey water will drain into your black tank.

As noted above, this carries the risk that the combined wastewater will back up into your tub. It would be pretty easy to do this if you aren't frugal with your water usage.

Another option is to collect the gray water in a portable tank (i.e. "Blue Boy") and transport separately to the dump station. These tanks are also useful for emptying the black tank without moving the trailer on extended stays. On the other hand, depending on your water usage habits, you may find that they require excessively frequent emptying due to their smaller size.

Another common option is to retrofit a permanent gray tank. There is room just behind the axles of your Overlander to install a gray tank of sufficient size to allow for considerable onboard storage.

I opted to go the latter route and spent about $400 for a 30 gallon tank and mounting pan. I had completely gutted the trailer and planned to replace the plumbing anyway so it made sense for me.

Twinkie's hybrid solution sounds like a good option as well.

Please feel free to ask any questions and enjoy!

[xrvr]

My suggestion earlier is no different tan the combined tanks on some b vans and Bambi's. Same idea, exactly the same thing. So some of you are saying the combined tanks from the factory are unsafe? Jim

[xrvr]

The combined tank on our 2006 Interstate would overflow if we were not smart enough to keep track. Just involved cleaning the shower stall really good to relieve the mess. Jim

[marioandpati]

Thanks for all the responses. We are pretty busy this moment but we will ponder all the suggestions and get back hopefully this evening. Once again thanks for sharing!!

marioandpatti!!!

[Jammer]

Originally Posted by zigzagguzzi

My suggestion earlier is no different tan the combined tanks on some b vans and Bambi's. Same idea, exactly the same thing. So some of you are saying the combined tanks from the factory are unsafe? Jim

Zig, the trailer in question has a black tank that is installed partially above floor level, so the usable capacity when in use as a combined grey/black tank is prohibitively small before sewage backs up into the shower. In contrast the B vans and Bambis where there is a single holding tank have the tank below floor level or (on some SOBs) have a shower pump.

The newer trailers with a single tank have some sort of provision for determining the tank level. In most cases the tanks are sized so that in typical usage the freshwater tank is exhausted before the holding tank overflows.

[marioandpati]

Thanks Kyle401 that is great information. We are looking for a somewhat temporary scenario for a year or two. We will be relocating the bath situation at some point in the future (We are planing to keep this one for a while!) so we did not want to spend the effort on a grew tank right now. Your solution, if the parts are available, should cover what we are looking for. We will be using the facilities sparingly, so we just need some storage, which the black tank should be able to provide. Do you perhaps know the storage capacity? We will be replacing the toilet this weekend and I was going to attempt to figure it out, but if you have any knowledge it would be appreciated.

Thanks again!

Mario and Patti

[Kyle401]

Originally Posted by Jammer

Zig, the trailer in question has a black tank that is installed partially above floor level,

The black tank on the '69 Overlander is completely beneath the floor. The '69 Overlander was offered only in a rear bath configuration with mid twins or a mid double bed configuration. http://www.airstream.com/files/libra...d62ecbae8c.pdf

Originally Posted by Jammer

The newer trailers with a single tank have some sort of provision for determining the tank level.

I'm not sure about all the trim levels, but my International Land Yacht was factory equipped with a black tank level probe.

[xrvr]

I thought the tank was below the floor, it was on my old trailer, and think it s on this one. Jim