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Green Toilet

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  • Green Toilet

    Hey all...

    let's just say that I setup on the roof of my house (with proper support and re-inforced structure) a tank to collect a certain amount of rain water. would simple gravity be able to fill the toilet tank? would there be enough pression to flush?

    just curious!

  • #2
    Re: Green Toilet

    if done right and the tank is higher than the tank of the toilet the answer is yes, as water will seek it own level, most toilets flush via the water in the tank and its volume and pressure, (actually it is the syphon that flushing the toilet on most older designs, water fills up the trap and the water over flows the trap and the column of water is then pulled by gravity out of the bowl of the toilet, some of the low flow toilets do work differently,
    see picture for a side view of a gravity toilet). picture and more information at,

    I have a storage tank on the farm here that is about 20' tall and if full it will gravity feed the upstairs toilet, (it my take 30 Min's to fill it tho as there is only about a pound of water pressure do to the placement of the height of the house and so on), (a little over 2 feet of elevation per pound of pressure)
    Each foot of elevation change is equal to 0.433 PSI of water pressure.

    but unless you have a roof to catch water on then fill the tank you will need a lot of rain to keep up with a toilet, and I would think a fair sized tank at that, (IF that was the plan, I would probly run the water through a filter, and has some type of change over device to keep the toilet working in the event of the tank running empty of rain water).
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    Last edited by BHD; 04-16-2008, 12:23 PM.
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    • #3
      Re: Green Toilet

      Make sure it is legal... water rights for downstream users can make use of catchbasins illegal.
      This is my reminder to myself that no good will ever come from discussing politics or religion with anyone, ever.


      • #4
        Re: Green Toilet

        just a thought. instead of putting the catchment tank on the roof why not divert the downspouts to a ground level tank and use a 12V pump (solar panel charged) to fill the toilet(s)

        kinda like our cisterns.

        In the never ending struggle to keep the water flowing.... The Poo Poo Cowboy rides again!!!


        • #5
          Re: Green Toilet

          If you can put a big enough tank on the roof, you'll be able to crush everybody inside when it comes through. I don't suppose you'd run any of this past a building inspector . . .


          • #6
            Re: Green Toilet

            nah no worries!

            i was just wondering if this was possible or not... as BHD was mentioning... if it takes forever to fill up it's useless... but then gain... as stxrus mentioned it... a pump might be acceptable!

            At any rate... it is more for an experiement that a long term idea... but the day water will be more expensive than golf i will convert!

            many thanks! ur a great bunch of knowledgable people!