Other uses for Black Tank with composting toilet in General Discussion Posted August 13, 2020 1 hour ago, Overland said: It's been discussed several times before, but to my knowledge, no one has followed through with anything. I removed my black tank and use the space for storage, if that counts. I'm certain that something is possible, but only with a lot of work and lowered expectations. And I think that combination, combined with plentiful, inexpensive, and much simpler solutions for storing extra water elsewhere, is why no one ever follows up. Specifically to what you're thinking - I certainly wouldn't want to use the black tank for both fresh and grey water - I don't think you can sanitize it nearly as thoroughly as you'd need. I do think that you could fairly simply transfer fresh water from the black tank to the fresh, but you'd have to remove the drain connection between the black and grey tanks to prevent contamination, and then remove the check valve on the cleanout port so that you could use to it both fill and empty the tank. Perhaps replace it with a manual valve. And you'd have to add an overflow of some sort. But if you did all that, then you could just simply run hose from there to the boondocking port and pump the water in. But, I think that's a lot of trouble when compared to a couple of $15 plastic jugs in the bed of your truck. Yep - definitely good points and sounds like far more trouble than it's worth. Taking the tank out and using the space for storage definitely counts! The reason I started thinking about this was storage space in the first place - trying to conserve some space in the back of the truck if possible.