The Waterless Toilet: 5 Options for Greater Sanitation with Little or No Water

This post is sustainablog’s contribution to Important Media’s celebration of World Water Week.

Like many of my peers, I was pretty excited when the Gates Foundation announced its “Reinventing the Toilet” initiative (which our sister site Ecopreneurist covered very thoroughly). As the Foundation’s video introduction (above) notes, the lack of sanitary means to handle human wastes sickens or kills many people in the developing world.

We’ve got the sanitation part down here in the US… but it comes at the expense of our water resources: even with the rise of low-flow and dual flush technologies, toilets are still the biggest water hogs in our houses. The EPA notes that the toilet alone can be responsible for up to 27% of our home’s water use.

I don’t know how that compares to some other big users of water out there, such as agriculture and energy production, but it’s pretty clear there’s room for improvement on this front… and we don’t have to sacrifice sanitation to make those improvements. In addition to the water that goes down the drain (and, again, following with the Gates Foundation’s objectives), we’re also flushing a lot of useful material… yep, there’s energy and useful chemicals in those unmentionables.

So, in the spirit of recognizing the flush toilet as a tremendous advance for its time, but one that’s prety limited in this day and age, I’d like to take a look at a number of waterless toilet technologies that already exist… and that also put our wastes to good use.


This is about as basic as it gets: using a bucket for a toilet (and, yes, I’ve done this… it’s pretty standard up at Dancing Rabbit). But that bucket is filled with sawdust (and you keep a bit more nearby for “flushing”), and when it’s full, you can add it to a compost pile or bin. Eventually, you’ve got garden fertilizer… which, yes, you can even use on edible plants.

Despite what Joseph Jenkins, the author of the Humanure Handbook, says, it does smell… not nearly as badly as you might think, but more than we pampered Americans want. But it’s also the cheapest and easiest way to completely cut the water use of a flush toilet, and “close the loop” on human waste. Time did a good overview a couple of years ago.

The Composting Toilet

A step up from humanure, the self-contained composting toilet also turns wastes into useful food for soil… but doesn’t require regular hauling of a bucket outside. The phrase itself is a bit of a catch-all: their are various designs, and a number of different features that manufacturers may offer (including some that use a little water). All use aerobic decomposition to break down wastes (as well as toilet paper), and can hold and process wastes for months or even years.

Downsides: first, they’re pricey. Second, you’ll still have some smell. And, finally, they do require more regular maintenance than they typical flush toilet. The EPA has a useful fact sheet on composting toilets.

Incinerating toilets

While this option is also water-free, and doesn’t have the smell issues associated with it, it’s got some definite disadvantages from a sustainability perspective. Obviously, to incinerate something, you need fuel: these toilets use electricity or gas to burn up the waste.  Secondly, there’s no real closed loop benefit: while its easy and safe to dispose of the ashes, the burning of the waste takes the nutrients with it. The EPA also has a fact sheet on incinerating toilets.

The Methane Harvesting Toilet

This is a new one that I came across while searching for green tech finds back in May. The Loowatt (currently being tested in London) could be called a composting toilet, but it uses anaerobic digestion to harvest methane from human wastes that can then be burned like natural gas. Only disadvantage I can see right now is the need to empty the storage canister more frequently than a conventional composting toilet.

The Solar-Powered, Hydrogen Producing Toilet

OK, this one’s not waterless… but it does make much better use of water than the traditional toilet, and also produces energy. The researchers developing it at Cal Tech are among initial grant recipients from the Gates Foundation program, and it’s pretty easy to see why. Using solar power, the unit not only cleans the waste water “up to the same level as would come out of a treatment plant,” (so it’s reusable) but also produces hydrogen from the waste itself.

There’s a lot going on in this space, even before the Gateses started offering money… if you know of something I missed, either in use or in development, show me up in the comments.

Other World Water Week Posts from Important Media Sites

Photo credit: cod_gabriel at Flickr under a Creative Commons license

  1. Klaus Reichardt

    Hi Jeff,
    yes, this discussion needs to be furthered and more disseminated. One item that is not listed but should be mentioned are urinals. A urinal is used in a public facility 3 times more often than a toilet plus in a home we use the toilet for urination ,therefore flushing precious drinking water again about 3 times more often than needed. Waterless No-Flush urinals have been on the market for the past 20 years and more and more home sales are being recorded. Cheers

  2. Buildingwell.org (@Buildingwell)

    This is a great collection of various near-watertless toilet technologies out there. While there are various pros and cons to each, one of the biggest cons for all is getting a viable and willing audience in the West. People have become so secure in their traditional toilets that any other non- or near-nonwater toilet may seem as a step back for them. These options can be great, but it will require considerable education and time before there is wide spread acceptance.

    As Klaus notes, there are also the no-flush urinals. This area is certainly growing as we’ve seen more and more of them installed in green buildings. It is one way to help shift opinions regarding the toilet.

    1. Jeff McIntire-Strasburg

      Yep, I knew I was just scratching the surface here. Smell seems to be the biggest challenge – it’s really not that bad in the first two options, though we’ve got so used to “flush it and forget it” that it takes some adjustment.

  3. Oliver Sylvester-Bradley

    Hi Jeff,
    We’re really excited to see what comes of the Gate’s call for solutions. The main problem does not seem to be a lack of product solutions tho, but how to roll them out throughout the developing world. One obvious ‘triple win’ solutions is waterless loos, coupled with micro-AD plants (which make gas, which is used to heat water) to provide clean, warm showers. This type of set up, which is being trialed in Ghana, provides clean sanitation, washing facilities, keeps waste out of the water system, and provides employment for an attendant.
    Thanks for your post – keep up the good work!

  4. Marta Ford

    It’s great that in the future using of clean water won’t be necessary in the toilet. I read that 30% of the water in the house is used in the WC, which is really big despoliation.

    Best regards!

  5. deborasmith

    By placing one or two plastic bottles
    (top removed) inside the water container can save a lot of water. This way, the water inside
    the bottles won’t be flushed whenever you push the button. Make sure the
    bottle stays under the container’s water level so the water inside it
    doesn’t become stagnant.

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