Tuesday, December 7, 2010

Where does all our water go?

I found a nifty site today, called All About Toilets. Charming, huh? I wish I could cut and paste their chart. They have a great graph of Daily Residential Indoor Water Use (which I would retitle, "Where does all our water go?") According to their statistics, in homes that do not conserve water, 26.7% of the water used goes to flushing the toilet. That's 91 gallons a day for the average American household.

So let's just start there. Because some of you will be surprised by the feature of our home that I'm choosing to share about today, and maybe that statistic will help you understand our choice a little bit better.

A visitor to the bathroom in our home is quick to notice unfamiliar territory: that of the composting toilet. Look carefully. See, no handle to flush?

Our unit is manufactured by Clivus Multrum, a leader in the composting toilet industry for over fifty years. Their toilets have been used in parks, commercial buildings and homes.

But what is a composting toilet?
It's exactly what it sounds like. It's a compost pile for people waste that is given the right conditions (temperature, moisture, time, etc.) to allow the material to break down fairly rapidly.

The composter tank itself is the holding tank in the basement. Two chutes (one from the first floor bathroom, one from the second) channel bathroom waste into the tank. We add wood shavings; an automatic sprayer adds the right amount of water; air is constantly pulled through with a fan. Bacteria and beneficial organisms convert the "organic material" into a much smaller volume of compost. Aerobic decomposition at its finest. It's a simple process.

(Please excuse the plywood. We're in the middle of a project.)

(Photo from the front of the tank. The black square door is the access port to the compost pile.)

There are three common questions we get about our system:

Does it smell?
Hard to imagine that it doesn't, isn't it? But it doesn't! Remember---you only get a smell of decay from anaerobic decomposition, when something is stagnant and not exposed to air. On this unit, there is a fan pulling air through the chamber 24-hours a day. That constant motion of air keeps things breaking down aerobically and there is no buildup of odor. Phew!

How often do you end up emptying the tank?
I can't truly answer that for this specific tank, because it's been a year and a half, and we're nowhere ready to empty it. When Fred and I had a smaller model composting toilet at Terra Dei, we emptied it out after a few years. Know how much compost came out? Less than two buckets.

What do you do with the compost?
Fair question. I know some people are cringing in front of their screens, thinking, "I'm never eating anything from her organic garden again!" Relax...
---First, I would never put compost of this nature on any food-related plant. It's just a mental turnoff. (However, just for sharing's sake, the Center for Biology of Natural Systems at Washington University in St. Louis carried out extensive tests on Clivus systems and end products. The bacteria found in the end product are the same that you find if you go dig a shovelful of dirt outside your house.)
---Second, we have a contract in place for a waste management company to come remove the compost from the chamber every few years. This was required by our sewage enforcement agency when they agreed to approve our application.

We realize that not everyone will be able to embrace the idea of the composting toilet. What if you happen to fall into that category, but still care about the environment and want to reduce the amount of water you flush down the toilet?

Thanks to the writers at the National Wildlife Federation, here are some tips for saving water in your home:

"You can save water wherever you live. If the owners of a typical 10-year-old home installed water-efficient toilets, dishwashers and clothes washers, they could save 18,700 gallons yearly, the U.S. Department of Energy says. Also, every month a family of four can save the following amounts by:

Fixing leaky faucets and toilets that flush themselves: 500 gallons
Running your washing machine only when it is full: up to 2,400 gallons
Keeping your shower under 5 minutes: up to 1,000 gallons
Installing low-volume toilets: about 480 gallons
Installing a low-flow showerhead: more than 2,000 gallons
Turning off water while brushing teeth: 800 gallons
Ensuring that your toilet flapper isn’t sticking when flushing: 900 gallons or more
Turning off the water while you shave: more than 400 gallons
Total saved monthly: more than 8,500 gallons"
(Source: www.nwf.org)

Thanks for visiting!

Clivus Multrum Incorporated
15 Union Street
Lawrence, MA 01840
(As always, you may assume that I was not compensated in any way, shape or form for writing this post. I am thrilled with our installed system, and just wanted to pass information along. Thanks!)


  1. I had to laugh at the tip, "Running your washing machine only when it is full." I can't remember a day my washing machine wasn't full with more than enough left over to do a few more loads!

    Thanks for the great posts. Very inspirational. We have to schedule a date in the new year to talk with you & Fred about the feasibility of using many of the techniques you have used in your home in our farmyard! Sounds silly, but as we expand our direct market sales, we need to look at modifying our farmyard to accommodate our clients, which may need to include adding a bathroom. We're also still very interested in exploring straw bale construction as a possibility for a new building. Once the holidays are over and the winter weather isn't such a threat, we'll have to get together for a long chat! Have a very Merry Christmas!

  2. You have definitely answered my questions! It is really interesting. If you think about it, all kinds of things are decomposing around us all the time, and compound that with how long the world has been around and all the things that have manured and died that are now the actual food we eat and water we drink--we are all made up of organic materials after all.
    I agree, I like to have what I can control many steps away from my garden as well.
    Great series of posts! thanks

  3. These posts are fascinating. Thanks so much for sharing! Hubby wants to know what you do with your gray (white?) water - do you have a sand mound or drain field or something for all of the water from your sinks/dishwasher/washing machine?

  4. Jen---I would love to catch up & hear about your future plans for the farm. Maybe a day in January when there is no two-hour delay!

    Cathryn---You summed it up so well! We really are on that giant cycle of decomposition and renewal, and we are such a tiny piece in the biggest of pictures.

  5. Kirsten, great question! At our first straw bale home we did have an experimental permit from the state for a graywater system that included an inside filtering tank and an outside sand mound. They only allowed us to do that because it was for the Environmental program my husband teaches. When we tried to apply to do the same thing here, on a purely residential system, they wouldn't allow it. That totally would have been the way to go. So even though our home only produces graywater, with no chance for blackwater, we still had to put in a septic system.

  6. I love the info about the cistern. The price you list is significantly cheaper than well prices from people nearby the land we are buying and I have always liked the idea of capturing rainwater anyhow. I think that's a winner for us. The composting toilet is also interesting though I think we probably can do a septic pretty cheaply and easily. Any chance you'd give details on the cost of that too? Also, what do you do with your gray water? Does it go through some other treatment or do you have a gray water well? Just curious on that as well...

  7. Well rats...I just saw your answer to Kristen regarding gray water. Sorry for the extra post...

  8. OK... so I know this is an old post, but I was just showing my engineer husband this and he had one obvious question I didn't think about.

    If you don't use any water to flush, how does solid waste go to the composter? Looking at your photos, it looks like there are curves in some of your pipes, so it's not like a direct hole from toilet to composter. So, out of curiousity, how does that work?

    Thanks for the great post and all the info!

  9. Hi Cynthia-
    No problem. Actually, look again at the pictures. The white pvc pipe you see is actually connected to the fan. Nothing but air passes through that pipe. Now look next to the white pipe, and you'll see a dark green chute about a foot in diameter. There are two of these on the top of the toilet, one from each bathroom. They're not exactly straight down, but they're pretty close.
    In fact, they're so straight down that I was actually afraid to move into the house with a two year old. Can you see that headline in the paper---"Two year old boy falls into composting toilet".