When we moved into our current home, each bathroom was its own color: sky blue, bright red, and teal. That included the sink, tub, and toilet. With five people in the house, using the toilet only three times a day, multiplied by an average of four gallons per flush, we used 21,900 gallons of water a year, not including showers, laundry, or dishes.

Over the years we’ve remodeled the bathrooms, replacing the toilets with more efficient ones that use a lot less water. Still, we’re wasting thousands of gallons a year of perhaps the most precious natural resource we have.

This time we’re going with a composting toilet. It is what the name implies: waste, through various chemical processes and a little time, becomes soil.

The low end of composting toilets requires only a bucket and peat moss. A mid-range toilet requires frequent emptying, possibly before the waste has finished composting.

High grade composting toilets are expensive—relatively speaking. The one we are currently looking at http://www.envirolet.com/320.html is around $3,200 (on sale through tomorrow).

That is considerably more than we had wanted to spend (three times the amount of the materials for the shell of our cabin), but it’s still cheaper than a septic tank. And rather than empty the waste ourselves, a solar-powered battery will suck it out of the house and into a composter. The great thing is, it only has to be emptied once a year, after it’s through composting.