Although there's nothing like the real thing, some imitations
are better than others — especially when it comes to
low-flow flush tests.
While previous toilet trials used sponges, plastic balls, and
construction paper as test media, a recent study by Veritec
Consulting and Koeller & Co. used extruded soybean paste
and wads of toilet paper — arguably a more accurate
replication of the real demands on a toilet. The researchers
assessed more than 90 models that meet minimum certification
requirements in the United States and Canada. The data is
presented by flush type (gravity vs. pressure-assisted) and
volume (1.6 gallons vs. 1.1 gallons), which makes the study
particularly useful as a specifying tool for builders and
remodelers. (The entire study, which is updated every four
months, can be viewed at
"Maximum Performance Report.")
Listed above are the top 10 performers
of the 90-plus toilets tested, with gravity-fed models
highlighted in orange. Each of these flushed more than 850
grams of the soy-based test media (above), exceeding the
250-gram threshold set by the researchers.
The researchers focused specifically on flush capacity, and
their performance threshold reflected a real average maximum
fecal size. Those toilets that met that 250-gram threshold
— meaning that they completely removed more than 250
grams of "waste" — passed the test. Results varied from
125 grams to 1,000 grams of waste successfully flushed in two
out of three attempts.
More than 20 models didn't achieve the threshold, suggesting
that a certified toilet won't necessarily meet consumer
expectations. Still, many passed with flying colors. As is
typical in this sort of toilet trial, the top performer was a
pressure-assisted model. But, notably, the 10 highest scorers
included four gravity-flush models (see chart, left), an
indication that low-flow engineering has improved a lot since
federal law mandated its use in 1994.
This is good news for builders shopping for less-expensive,
reliable fixtures: You don't have to choose the noisier
pressure-assisted technology to guarantee a good flush.