NAHB Researchers Tackle Toilets

The study was commissioned by Seattle Public Utilities and the East Bay Municipal Utility District of Oakland, California to “develop information on product performance, water savings reliability, and physical characteristics that will assist the consumer in evaluating products and making purchase choices.” To achieve this objective, researchers employed a legion of sinking sponges, floating sponges, and paper wads at five levels of loading to simulate the range of waste toilets are designed to handle. Two units of each model were tested for their ability to rid the bowl of test media.

Despite its disclaimer that “determining a threshold for satisfactory performance was beyond the scope of the study,” the report applauds 35 models that performed best. The report concludes that “there appears to be little correlation between fixture price and flushing performance.” The top 35 models represent 14 manufacturers and include all tested flush systems. All three ultra-efficient models the researchers tested—a 0.5-gallon-per-flush (gpf) (1.9 liters per flush or lpf) model from Microphor, a 1.0-gpf (3.8 lpf) model from St. Thomas, and a 1.4-gpf (5.3 lpf) model from Toto—came out among the top 35 performers. Toto swept the top three places with its Ultimate Elongated Bowl, UltraMax, and Ultimate Round Bowl models.