Is your seat down? Good. Let's sit and think. In the old days residential-use toilets in the U.S. were designed to unleash anywhere from 3.5 to 7 gallons per flush (GPF); the low-flow movement took off in 1994, when a federal statute kicked in requiring that new units employ no more than 1.6 GPF. How often do people use their toilets? Here we face the thrilling diversity of human experience: some pee four times a day, some ten, while anything upward of three bowel movements a week is considered normal. The bottom line is that for practically everyone the daily ratio of (shall we say) liquid-only events (LOEs) to solid events (SEs) is greater than 1:1, and for some may be 6:1 or more. For argument's sake let's say a typical day on the toilet involves five LOEs and one SE. Using a 3.5 GPF unit that consistently gets the job done in a single flush, that's six events, six flushes, for a total of 21 gallons. But the puniest low-flow model should have little problem handling the LOEs, so even if five flushes were required to bring the SE to a satisfactory conclusion, the ten flushes would use only 16 gallons. In this scenario, as long as you're flushing fewer than eight times per SE, the low-flow toilet is saving water.
Obviously, hanging around repeatedly flushing a toilet is practically no one's idea of a good time (cats on YouTube notwithstanding), but there's evidence to indicate that the typical low-flow user's experience hasn't been quite so grueling. It's true that some of the first low-flows were pretty dodgy — often manufacturers just stuck a new valve or dam mechanism in an existing model rather than revamping the bowl and other elements to work with the reduced flush volume. While the resulting units did conserve water, satisfaction with them was mixed, and anecdotally at least they acquired a bad rap. In 2000 University of Arizona researchers conducted a study measuring water use in 170 Tucson households where low-flow toilets had been installed seven years earlier. Among their findings: (1) more than half the homes had no detectable toilet trouble; (2) about 11 percent of the low-flows got double-flushed at least once a day, somewhat but not much more than the rate seen for higher-volume models; (3) low-flows were seemingly more prone to developing flapper leaks; and (4) in over a quarter of the homes at least one of the low-flows was using significantly more than the 1.6 GPF it was meant to, whether because of malfunction or tampering.
Let's reduce the tone and rhetoric... like the "grow up" comments, folks.
