Reply #4: Well, I was thinking about that

[ashling]

the tank probably wouldn't need to be much larger (if at all) that a water heater: 40 or 50gal. Each bath is maybe 10 - 20 gal., but you would be draining it all day at about 3 gal. per flush. Actually, you could use one or two used water heater tanks for this (maybe up to 100 gal for peak use, like in the morning when everybody is using the shower, etc. You would need a pressurization system that shouldn't take up too much space, so an area not much larger than a water heater closet (or 2) The cost, (and headache) would be all the replumbing you would have to do. It doesn't seem like it would be too major, but I always assume that it is going to be way more complicated than it seems at first. Well, actually, I don't ...then I wish I had. LOL

Come to think of it, you are probably going to have to have one tank to hold to stuff that drains by gravity, and a pump to pump it into the second tank (and maybe a backup. You want to make sure that your storage capacity is larger than you will ever need (so forget what I said up front ... see what I mean about assuming?) If the storeage tank were above the level of the toilet tanks, you wouldn't need any special pressurization - just the pump.

I am sorry if I am going crazy with this, but we used to have our own place in the country and I would do projects all the time. Since we sold that place and went back to school, I need an outlet for all these pent up plans LOL

anyway, good luck.