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Composting Toilets for Off Grid Homes

By: Everett S
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Sunmar Composting Toilet“Water, water everywhere” defines the contemporary approach to dealing with human wastes. We use clean, potable water to send the nasty stuff “away.” If you’re living off-grid, though, you may have a great appreciation for the availability of water. If you’re collecting it in rain barrels or a cistern, or even using a well, you want to use it even more efficiently. Water-efficient toilets certainly help, but if you’d rather not waste water on your wastes, composting toilets provide a low-water, or even water-free, alternative that also allows you to close the poop loop by turning bodily wastes into organic material ready to go back into the soil.

The DIY Composting Toilet

DIY Composting Toilet with Bucket

A DIY composting toilet is as simple as a bucket with some sawdust. Building a box around it and including a lid and seat makes go-time more enjoyable.

If you’re living off-grid, or want to, you’re probably already a do-it-yourselfer… so why not build your own toilet? You can find a number of easy-to-follow plans with just a few clicks of your mouse. A few resources about composting toilets for off grid homes include:

  • The Humanure Toilet: The Humanure Handbook has become a classic among off-griders, and this plan, complete with images, shows why: all you need is some lumber and a toilet seat.
  • The Green and Recycled Materials Toilet: Wikihow has a fantastic plan (with photos) showing how to build a composting toilets out of mud, plastic bottles, an oil drum, and bamboo.
  • The 55-Gallon Drum Toilet: The National Water Center’s DIY plan is a little more intricate, but also very thorough.

Composting Toilets for Purchase

Not quite ready to take on the challenge of building your own toilet? No problem: a wide range of composting toilets are available for sale. They can be a bit pricey, and often require some energy use, but you’ll likely encounter fewer issues with odors. Among the brands available:

  • The Biolet Composting Toilet: Biolet‘s been in business for about 20 years, and makes a range of electric and non-electric toilets. A non-electric model can run you $1400; electric models will run at a least a few hundred dollars higher. The company itself has a collection of testimonials; some reviewers have criticized non-electric models for odor (which is common), and electric models for fan noise.
  • The Sun-Mar Composting Toilet: Sun-Mar‘s been around for almost 40 years, and features a product range of 22 toilets. The prices ranges are comparable to Biolet’s. The company’s engineers have focused on odor reduction, and Sun-Mar has received certification from the National Sanitation Foundation International for “liquid containment, odors, and solid end products.”
  • The Clivus Multrum Composting Toilet: BuildingGreen.com described Clivus as “the pioneer in composting toilets”; at the same time, it notes that its technical innovation hasn’t always matched that of its competitors. It’s focused on commercial and institutional sales more than residential, though the latter category makes up about 10% of sales. The system uses gravity to move wastes, so it’s necessary to have (or be able to create) a large space below the toilet’s location.
  • The Envirolet Composting Toilet:Looking for a composting toilet that’s not radically different from a flush toilet? Envirolet’s “Flushsmart” toilet (which is pricey — over $3000) closely mimics the traditional toilet, while using considerably less water. Envirolet’s FlushSmart toilet is a vacuum flush and composting toilet system combined.

Other brands include EcoTech, Phoenix and Nature’s Head (primarily for boats and RVs).

Amazon.com usually has the best deals on composting toilets since so many manufacturers and distributors are competing with each other in the same marketplace. It’s also a good source for composting toilet reviews. Check out composting toilets on Amazon!

Also check out our list of composting resources, our toilet-lid sink review, and our intro to composting toilets.

Use an off-grid composting toilet (or other form of waterless toilet)? What are your impressions and suggestions? Share your thoughts below…

Jeff McIntire-Strasburg is the founder and editor of sustainablog, a long-running green blog which now generates its revenue primarily through the sale of eco-friendly products. You can follow him on Twitter @sustainablog

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Category: Renewable Energy, Sustainable Living

Comments (9)

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  1. Chris Muir says:

    Hello Off Grid Ebert:

    Nice article, great for awareness. I do have a couple of comments though. I see you’ve used our diagrams for “self-contained” and “central” composting toilets — they are really old and we could easily update them if you wish. Next, your description of the Envirolet system is completely inaccurate — it is not a carousel-type system, you should recheck that.

    I am glad to see that you mentioned the National Sanitation Foundation, because that is truely the benchmark for a successful composting toilet. Also, be sure to note the difference between certified and listed by NSF vs. certified TO NSF standard 41. See the following link for a good explanation:
    http://www.nsf.org/consumer/newsroom/pdf/fact_gl_composting_toilet.pdf

    Thanks for a good article!

    Chris Muir

    Sun-Mar

  2. Jared says:

    If you are thinking of purchasing a pricey factory made composting toilet I have got a couple of tips for you. First of all consider spending less cash and building your own system. It will probably work better and you’ll understand it well because you built it. Secondly, do a lot of research first before you buy anything. Everyone will of course advertise that their composting toilets are easy to use, odor free and highly efficient but in reality the experiences of many people with composting toilets has not been that dreamy.

  3. Uncle B says:

    Sweden has dry composters for humanure in operation as we speak! Humanure can be bio-gassed into consumer gas if you can get enough of it. Free books and info on net abound on humanure. Oslo, Norway, run their public buses on bio-gassed humanure! Processing humanure to good safe compost for gardens is so possible! Not distasteful if done properly. Sweden also bio-gases wastes. Bio-gassing end products include safe, topsoil building fertilizers. Only oil-rich Americans waste these valuable resource flows! The 18th century “Crappier” we use daily, takes 16 gallons of good drinking water to do something a handful of bacteria can do just as well – under the right conditions. We will learn of this if we try to go to Mars – suddenly it will become acceptable? Biology holds the answers to our future, not “Cheap Oil”

  4. stuart goldhawk says:

    This is the first time that I have seen a toilet like this.I think more peolpe should be made aware of the practicalities of these systems.

  5. Carpet Cleaning Melbourne says:

    OFF-THE-GRID TOILETS: I dream of living off the grid, this site has a great mix of links and solid information. From DIY to off the shelf options

  6. eric gunsalus says:

    I HAVE A QUESTION FOR ALL COMPOFESSIONALS OUT THERE. COMPOSTING TOILETS ARE NOT LEGAL EVERYWHERE. THE ONE QUESTION I ALWAYS RUN INTO IS” WHAT HAPPENS TO THE LIQUID?”. DARN GOOD QUESTION. THE WASTE IS CONTAINED,BUT WHERE DOES THE LIQUID GO? 2 OR 3 PEOPLE LIVING IN A HOUSE – LET’S SAY A HALF GALLON A DAY( 15 GALS PER MO.). CAN A SMALL(100 GAL TANK?)BE INSTALLED UNDERGROUND SO THAT URINE & ANY WATER USED CAN DRAIN & BE PUMPED OUT LATER(WHEN ENOUGH HAS ACCUMULATED)?

  7. Kevin Ison says:

    The liquid end product from the composting toilet is usually piped in with the household greywater and treated in a reed bed or planted area.

    There is not that much unless the toilet is situated at location where plenty of people just go to pee. Also, you do need to have bulking agent like sawdust. 1/2 to 1 cup per pee.

    The greywater is not as bad a blackwater from a septic tank. We have used this type of system in Africa with Bananas, melons, tomatoes and other fruits growing.

    It worked a treat with underground soakage pipe.

    Be careful of root intrusion as roots love the waste water.

  8. Rebekah says:

    A Biolet came with our cabin. We were all excited about it until we figured out that it quits composting when temps drop below 60.

    Read up on all the factors necessary in making the composting process happen. If you’re off-grid, a heated/fan unit might be an option, if they make a battery operated one. As for us, we’re taking ours out.

  9. Rebekah nothing beats a five-gallon bucket and some sawdust. You can build a box around it with a toilet seat on top and nobody will ever know. Hook a fan up and you’re in business.

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