Toilets consume 30% to 40% of the total water used in homes, making them the biggest water users. Replacing an older 3.5-gallon toilet with a modern, low-flow 1.6-gallon toilet can save an average of two gallons-per-flush (gpf), saving 12,000 gallons of water per year. Low-flow toilets usually have 1.6 gpf marked on the bowl behind the seat or marked inside the tank.

Another method for reducing the volume of water used with each flush is to install a water-filled plastic bag (called a displacement bag) in the water tank. The old version of the displacement bag was a brick.

Pressure Assist Toilets

These are the most powerful toilets, best suited for large families or heavy use.

The toilet's water supply provides the pressure to compress air within a sealed plastic reservoir inside the tank. When the incoming water reaches the fill line, the tank is pressurized and ready for the next flush.

Although pressure-assist toilets somewhat noisy during flushing as pressure is released, up to 80% of the flush water is used to purge the bowl, making for a very efficient flush.

These toilets work well as long as the household water pressure is at least 25 pounds per square inch (PSI). Pressure-assist toilets can solve problems in homes with older plumbing systems where gravity-fed 1.6-gpf toilets just aren't strong enough to pull waste through the older pipes.

Pressure-assist toilets are generally better than typical gravity toilets, but the more complicated mechanism make them more expensive to buy and repair.

Pressure-assist toilet with top button

Pressure-assist toilet w/side handle

Vacuum-assist Toilets

Vacuum-assist toilets have a vacuum chamber which uses a siphon action to suck air from the trap beneath the bowl, allowing it to quickly fill with water to clear waste. Vacuum toilets are relatively quiet.

Vacuum-assist toilet (note reservoir)

Dual-flush Toilets

Dual-flush toilets have been in Europe and Australia for years, but are now gaining in popularity in the U.S.

Dual-flush toilets let you choose between a 1-gallon (or less) flush for liquid waste and a 1.6-gallon flush for solid waste. Dual-flush 1.6-gpf toilets reduce water consumption by an additional 30%.

Source

Dual–flush toilet

Composting Toilets

Composting toilets are not connected to a separate waste system, but contain a tank in which sewage and waste are composted.

Unlike a septic system which uses anaerobic (without oxygen) bacterial activity to break down sewage and waste, composting toilets use aerobic (oxygen-using) bacteria and fungi which require that the waste not be completely covered with liquid.

Some composting toilets have multiple tanks which can be alternated so that compost can be completely reduced with less risk of infection by pathogens than is the can when only one tank is used.

Properly configured and used, a composting toilet reduces waste to between 10% to 30% of it’s original volume. The resulting product resembles soil, is stable and is called humus (HYOO-muhs). Although in many areas of the world humus is added to soil used for food cultivation, in the U.S. this is not allowed and humus must be disposed of as specified by the local Authority Having Jurisdiction (AHJ).

Composting toilet

MEASURING WATER FLOW

Determining the flow rates of faucets and showerheads is accomplished by holding a specially marked container beneath a plumbing fixture for a specific length of time, then reading the water level against markings on the container.

This Water-flow Measuring Bag is held under a plumbing fixture for 5 secondsUsing flow-limiters at showerheads and faucets can save many gallons of water over the course of a year in addition to reducing hot water heating costs. They’re available in a variety of flow rates- .5, 1.0, 2.0 and 2.5 gallons per minute (gpm).

Drip Gauges

Drip gauges work in a manner similar to measurement bags and convert drips to gallons per day (GPD) and gallons per year (GPY).

This Drip Rate Measuring Device is held under the drip for 5 seconds

These containers and are inexpensive and are available through companies listed under Sources for Information and Water Conserving Products at the end of this section.

GREYWATER SYSTEMS

Greywater is waste water from showers, tubs, sinks, laundries and dishwashers. “blackwater” is waste from toilets, urinals and bidets. Greywater can contain disease-causing microorganisms such as bacteria, protozoa, viruses and parasites or contaminants such as fats, oils, detergents, soaps, salt, nutrients, food and hair.

Because these contaminants can pose both health and environmental risks, greywater should be used only for certain applications, which may vary with the particular type of system installed.

Different greywater systems exist which use approaches ranging from a simple garden hose out the bathroom window to expensive installed systems. Because toilets are responsible for approximately 40% of indoor water consumption, these systems can result in significant reduction in annual indoor water consumption.

Greywater systems like the one in the photo above use a media filter to clean greywater for reuse in toilets. The filter and tank must be cleaned occasionally.

Source

This system does not supply potable water but filters greywater for re-use in toilets

All photos not cited by Kenton Shepard

Soures for More Information and Water-saving Products

Water Use Calculator- How much water are you using at your home? This calculator will give you a water budget for the inside and outside of your home. A water budget tells you the right amount of water you should be using. Compare the water budget to your actual water bill and see how much water you could be saving.
Water Wiser Drip Calculator- Offers 2 easy ways to convert water drips into Gallons Per Day (GPD) with no special equipment.
New Resources Group- offers incentive kits which include aerator and showerhead water-flow measuring devices, leak gauges and water-saving devices such as aerators, low-flow showerheads, and more all at very low prices. Good kits as give-aways for clients.
Niagara Conservation Corporation- offers aerator and showerhead water-flow measuring devices, drip gauges, water-conserving showerheads, faucet aerators, ultra-low-flow toilets, high efficiency lighting products, and various weatherization materials.
EPA WaterSense Program- is a voluntary partnership program sponsored by the U.S. Environmental Protection Agency. Its mission is to protect the future of our nation's water supply by promoting and enhancing the market for water-efficient products and services.
National Sanitary Foundation- Excellent, broad source of information of about water used inside homes. Covers conservation, quality, training and product certification.
Consortium for Energy Efficiency (CEE)- members are energy-efficiency organizations, including electric, gas and water utilities; researchand development organizations; state energy offices; and regional energy programs. Both the U.S. Environmental Protection Agency (EPA) and the Department of Energy (DOE) provide major support through grants and participation. CEE utility members develop energy-efficiency programs, using the residential initiatives as templates, and pass the savings on to their customers.
Learn more about greywater systems.

Peak to Prairie Home Inspection Service

Indoor Water Conservation