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Thread: Replacing composting toilets with low flush system

  1. #1

    Default Replacing composting toilets with low flush system

    My name is Jill and I am new to this forum. I recently purchased a home that has Biolet composting toilets and I am interested in installing a low-flush system. Does anyone know what is involved in going from a composting system to a low flush system? I can't seem to find any information online about what this would entail. Any help would be appreciated.

  2. #2


    It all depends upon what type of installation this was. Was this a retro-fit in a cabin or home that previously had standard plumbing? Or was this put in place in a home or area of a home that never had a standard, water using toilet? All that is necessary for the Biolet unit is a vent and electric connection. A standard toilet will need a drain w/toilet flange, a cold water connection and a vent. This will be very difficult (expensive) to install if there never was a water-using toilet there. You have vent, but it may not be usable, due to placement or what it is made of. Do you even have a sewer hook-up or septic field? If not then you really have an expensive proposition. Biolet toilets cost over a grand. Maybe some tree-hugger will buy your used one and help defray the cost of the changeover. See www.biolet.com for more info. Handyman, not a plumber.

  3. #3

    Default Low flush composting toilets

    Thanks for the information. There has never been any standard plumbing in the home-it was built for the composting units. I actually am interested in switching from the self-contained composting unit to low-flush composing units-sorry, I was not clear in my earlier message. Will this be as big of an undertaking (moneywise and timewise)?
    Again, I appreciate any advice!

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    New England


    My guess is that if the existing toilets do not have water plumbed to them and you do not have drain lines, then you'll need to add those and new vents. If you have access from below, then you could probably do this without tearing too much up. Otherwise, it is a big endeavor. Toilets require a minimum of a 3" drain, and 4" is considered better by some. Your existing drains probably are not sized to handle that if they only support showers, tubs and sinks. You may have to upgrade your entire waste system.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5


    Just curious, do you know why it was put in the house in the first place? Was if functional in the real world? Where does your other grey water go?

  6. #6


    Really can't help you much here, Jill. This seems to be leading edge waste treatment technology. It looks like Texas is doing some studies on its practicality. I believe it involves partial use of greywater to remove the composting toilet waste. I think you would (minimum) need new units, plus piping that would link your drain to the new toilet. Then a way to disperse it somehow, eilther into a septic type tank or for use as fertilizer. You need to contact someone who installs these systems. I'm all for being environmentally aware, but the biggest wasters/polluters/users of water are industry and agriculture. Why don't they start there when legislating water conservation?


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