Everything in Black and Gray

[dmaiden]

I may get the award for dumbest question ever. Let me preface by saying I do know the difference between black and gray water, and I understand you can remove those nasty lumps in the black tank by flushing with the gray,

HOWEVER,

Is there any other reason for having a black and gray tank, and not just one septic type tank since it all goes in the sewer anyway? I would call it a blay tank, or maybe a grack tank.

I'm sure there must be a reason since everyone does it, it's just not obvious to me.

Thanks, or should I say Tanks?

[CanoeStream]

Hi Dave -- Most folks would agree that the grey tank will fill several times before the black tank would fill once. I can say that 90-95% of any water tank fill ends up in my grey tank. Any excess grey water could come up thru the shower drain if I have a water hookup or carried extra water in jerry cans. A number of recent CCD-type models integrated the black and grey tank. I've never read any comment thinking that this is a good idea. The risk is that a full tank would result in a very nasty shower floor. You also wouldn't be able to or want to bleed off any grey water into a blue tank if you were getting full.

[InsideOut]

Okay...here we go:

Black Water = Toilet
Gray Water = Everything else

Yes, you can combine them and some trailers do. However, most people prefer to keep them separate for a couple of reasons - typically, you go through more gray than black. You can empty gray in more places than you can black. If they are combined, you may not be able to get rid of your "full load" thus not able to keep using it. If you are in a campground with full hook-ups this may not be a problem...but if not or if you are boondocking, you will have to pull-up camp to go unload.

With a '63 trailer, you probably don't even have a grey tank unless it has been retro-fit by a PO. Thus, using an exterior tank (blue belly, blue tote, etc.) is what you would use when you can't run your gray on the ground. I would much prefer using the blue belly with only grey than black too. That saves room for the black to be contained until you get to a dump.

Hope that helps...

Shari

[azflycaster]

Dave,
Anything that goes don the toilet is black water. Everything else (sinks and shower is grey). Your trailer was built with only a black tank. Back then no one had a problem with draining the grey onto the ground. Airstream did not include a grey tank in it's trailers untill the mid 70's. Some of the more recent units have just what you call a blay tank and I think it was done to save space. Here are what I consider an advantage of two tanks.

1. When I boondock I can empty the grey tank (into a hole in the ground). I would not do that with the black tank.
2. when my grey tank is full, my shower will start to fill with grey water. This is not great, but think about a shower full of blay water .
3. The chemicals that I use to break down the black water would not work well with the soaps from the grey water.

[dmaiden]

Shower with gray water not good, but not horrible.
Shower with black water disgusting.

thanks folks. I've been thinking about just doing the blue tote along for grey, but I'm stripping this thing to the bone and may end up putting one in.

thanks a lot. I'm sure a lot more to come.

[overlander63]

Originally Posted by dmaiden

Shower with gray water not good, but not horrible.
Shower with black water disgusting.

thanks folks. I've been thinking about just doing the blue tote along for grey, but I'm stripping this thing to the bone and may end up putting one in.

thanks a lot. I'm sure a lot more to come.

Dave, I combined the water out of the kitchen sink into the black tank on our Overlander, and so far it has worked very well for us. I would not recommend, nor would it be easily possible, to combine shower water and black water. There are advantages to running the dishwater into the black tank, namely diluting the stuff that is normally in the black tank for easier dumping, and being able to wash dishes, or hands, without being hooked up to a blue tote.
The disadvantage is, the black tank will fill up faster, and at a mere ten gallons it doesn't take many sinks of dishes to fill it.
Since your black tank is above floor level, and your shower is at floor level, if you combine the shower water and black water, the contents of the black tank will flow to the lowest level (bottom of the shower).
Some states will still allow you to dump shower water on the ground, or into a hole in the ground, as indicated above, but the dishwater has a much higher bacteria count than shower water, and holding it for dumping is much more environmentally responsible than letting it out with the bathwater.

[dmaiden]

Thanks Overlander. Didn't know that sink water was worse than shower water. I'll probably go with the blue tote for grey or put one in.

[ROBERTSUNRUS]

Hi, my one time experience; At one campsite they only had a space for me that had electric only. I was told by the owners, that it was OK to drain my gray tank to help water the trees. And when we left we drained the black tank at the dump station. This allowed me to stay in one place for the time we planned on staying in the first place.

Bob

[Safari Tim]

Originally Posted by dmaiden

thanks folks. I've been thinking about just doing the blue tote along for grey, but I'm stripping this thing to the bone and may end up putting one in.

Dave,

I've never had a trailer with a grey tank. My last one did not have one and my current Ambassador does not either.

So during my restoration I'm adding one (27 gallons). If you're stripping yours to the bone, I consider adding one while your at it.

I'm sure I'll love having one, but it will be a while before I know for sure!

[dmaiden]

Good point Bob. Thanks.

Yes, Ambassador Tim, Ali McGraw had it all wrong. Love means never having to say you're sorry AND having a grey tank.

I'll probably put one in. Just another task on the list. I should divide into price ranges: $50 tasks, $200 tasks, $400 tasks, etc.

[peegreen]

I saw a conversion on a SOB where the owner modified the plumbing so as to be able to pump the gray into the black. This way if there was still usable void space left in the black, and he needed extra volume in the gray, he could just pump whatever was necessary. I guess it was also good for flushing the black. Looked interesting, that's all.