In most homes, the single greatest use of water is for flushing the toilet. Older toilets may use three, five, or more gallons (liters) per flush. Toilets manufactured since the early 1990s have been federally mandated to use 1.6 gallons (6 liters) of water or less (see Figure 3.7). Some toilets on the market today use even less water per flush. Toilet manufacturers have improved the technology for toilet flushing systems to make them more efficient, effective, and quieter. An effective flushing system reduces the likelihood that a second flush will be used to remove all the waste. In addition to saving water, efficient and effective flushing systems reduce main­tenance.





1.6 gpf




(6) (Ipf)

ToiletsПодпись: FIGURE 3.7 The number of gallons (liters) per flush has decreased as toilets became more efficient. Norbert Lechner, Plumbing, Electricity, Acoustics: Sustainable Design Methods for Architecture. New York; John Wiley & Sons, 2012. ToiletsToiletsToiletsToilets

In a remodeling project, you may be replacing an older toilet that used more water in the flush. Make sure the water pressure is adequate for the new, more efficient toilet. Explain to your client that the new toilet may sound or operate differently. For example, some toilets have dual-flush systems that let the user choose the amount of water per flush. In some communities, the water authority may offer rebates for installing a more water-efficient toilet.


The early 1990s also saw new regulations limiting showers to 2.5 gallons (9.5 liters) per minute flow rate. Many fixtures offer even more efficient water-flow rates of 2.0 gallons (7.6 liters) per minute or less (see Figure 3.8).

When designing shower systems with multiple showerheads, put individual controls on each fit­ting. The user can then adjust showerheads to provide only the desired amount of water, reducing waste, especially of hot water. This is particularly important in two-person showers that may be used, at times, by only one person.