Sustainable (high efficiency) toilet technologies range from low to high-tech and everything in between. Even if you are out at Home Depot checking out what they have in stock, you will have options at your disposal to minimize your use of water. The least expensive options will still be considered low-flow toilets (more efficient) as compared to the types of toilets which were installed in homes built through the early 1990s. Toilets that were installed before that time may have used up to 5 gallons of water per use, however, by law toilets today are not supposed to use more than 1.6 gallons of water per flush.

5. Tricking Your Tank: An easy way to save a gallon or two per flush is to displace water in your cistern by inserting something solid in there, like a brick or a glass bottle filled with water, rocks or sand. Since conventional toilet tanks fill to a certain height level to achieve a proper amount of water pressure to flush effectively, the brick displaces some of the volume in the cistern that would have normally been taken up by water. For brick users, it’s recommended that you wrap the brick in a plastic bag in order to reduce the possibility of the brick disintegrating in the tank and damaging your plumbing.The following is my own ranking, from least to most effective, of the top five sustainable toilet options available today:

Composting Toilet, Photo Credit:

4. Low Flow Toilet: As mentioned above, low-flow toilets are required by law in the United States. Such toilets fall into two major categories: 1) Pressure assisted toilets and 2) gravity flush toilets. Pressure assisted toilets combine the water in the toilet with compressed air to force water into the bowl and blast the waste down the drainpipe. Perhaps because of the noise that can accompany a pressure-assisted flush, these toilets are more appropriate for commercial settings.

Gravity flush toilets are usually the least expensive to maintain and operate off of the simple premise that pressing the knob opens the flush valve in the tank causing water to drain via a siphoning action into the bowl through openings in around the rim. The force of the water jetting through the openings pushes the waste down the drainpipe.

In the early days, many supposedly “low flow” toilets did not function properly. They not only used more water than the 1.6 gpf they were supposed to use, but also left a lot to be desired (as in “I desire to not see poo in my toilet anymore after I flush it”) in terms of effectiveness. Apparently, this lack of performance created an attractive opportunity for one man, a hardy Canadian named Bill “The Flusher King” Gauley. Gauley’s dedication to testing toilets effectiveness at flushing everything from bananas to mashed potatoes to soy bean paste-filled condoms has led to the acceptance of his Maximum Performance (MaP) test being the universal bar that all low flush toilets must pass.

3. Dual Flush Toilet: The dual flush toilet originated in Australia and has been widely praised for its flexibility and efficiency. The premise behind a dual flush toilet is that liquid waste requires less water to dispose of than solid waste. Thus, the average male “specimen” (.55 lbs) would be subjected to a 1.6 gallon flush, while liquid deposits would receive about .8 gallons. The presence of this .8 gallon option may result in as much as 67% less water usage than a conventional low flow toilet. Dual flush toilets accomplish their job by employing a larger trap (hole) in the bottom of the bowl and use no siphoning action. Instead, dual flush toilets use a gravity fed, washing type action to push waste down the drain. These toilets are primarily found in Australia, Europe and Asia and are catching on here in the United States, thanks to increased awareness of the importance of water efficiency and various financial incentives in place.

2. Waterless Urinal: Waterless urinals were introduced in the early 1990s and have evolved to be categorized into two categories: 1) cartridge-based and 2) non-cartridge based. The basic premise behind a waterless urinal, for both categories, is that urine flows down into the urinal bowl and passes through a sealing liquid which is usually comprised of an oil based fluid or pure vegetable oil. In the case of cartridge-based waterless urinals, the cartridge holds the fluid and must be replaced once or twice a year, as the fluid breaks down and loses its effectiveness. According to some waterless manufacturers, the costs of operating a cartridge-based waterless urinal are less than they would be for a conventional urinal which must be constantly treated with “urinal pucks” or some other odor masking solution. With non-cartridge based waterless urinals, the fluid sits in the basin and the urine flows through naturally allowing the oil-based fluid to remain on top.

1. Composting Toilet: Probably the greenest type of toilet is the composting toilet. However, because our bodily functions are often treated as delicate topics, forcing us to contemplate what happens to the waste we produce (as opposed to having it “magically” disappear altogether) may present the composting toilet with one of the highest (psychological) barriers to broad market acceptance.

Composting toilets use little or no water and treat toilet wastes on-site for reuse as valuable compost. The benefits of using composting toilets are enormous. For instance, if an entire community were to embrace composting toilets, it would make unnecessary the need for a public sewer system in that community, reduce water usage by up to 40% and create fertilizer for use because the “waste” is converted into compost which is high in nutrients and therefore terrific for agricultural use. The potential negatives associate d with composting toilets include the threat of odors (indeed, normal with any toilet), overloading (if not maintained) and lack of broad acceptance by municipal authorities where sewer systems are available.


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Based in San Mateo, California, Ecovita specializes in urine-diverting, composting eco-toilets. Ecovita Composting, Water Saving
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