I realize I've already written about low-flow toilets once this year.
In case you don't know what I'm talking about, low-flow toilets officially crossed the threshold of the U.S. home in 1992, with the enactment of the Energy Policy and Conservation Act.
The act established water-use restrictions for new toilets, showerheads and faucets. The so-called EPAct set a national manufacturing standard of 1.6 gallons per flush for most toilets beginning Jan. 1, 1994.
EPAct effectively replaced the 3.5-gallon-per-flush toilets that had been the standard household fixture for years.
The decision was not universally welcomed, especially by consumers who complained that many models required multiple flushes to rid the bowl of waste. In addition, the toilets frequently clogged.
Manufacturers were slow to acknowledge the problem, but when they finally did, they began coming up with models that worked somewhat better than the originals.
Part of the problem with low-flow toilets is that EPAct wasn't accompanied by any measure of performance for the products to be developed, or any provisions to ensure that the new products would perform at least as effectively as their predecessors.
When I wrote the previous article, I talked to Bob Hill of the National Association of Home Builders Research Center in Maryland, who conducted a study of the toilets in 1999. While acknowledging the toilets' problem, Hill said the study had been neither comprehensive nor conclusive, and promised that another one was on the way.
The results of that study were published late last month.
The objective of the study, which was conducted with water districts in Seattle and Oakland, Calif., was to develop information on product performance, water-savings reliability, and physical characteristics that will assist consumers in evaluating products and making purchase choices, Hill said.
Testing of 49 toilet models involved determining the flushing performance, flush volume, trap diameter, water-spot area, and other characteristics.
Flushing performance was tested using a series of floating and sinking sponges and paper to simulate waste loading in the toilet.
A Flush Performance Index was developed, based on how much material remained in the bowl after flushing. Researchers also measured flush volumes after the original flappers were replaced with generic replacement flappers.
The study also included testing of three early-model low-flow toilets that had performed unsatisfactorily in individual residences. Two units of most major models were tested, and some variation in flushing was seen between units of the same model.
But most new models performed better than the early-model toilets included in the test.
While most of the tested fixtures were designed to flush at the standard 1.6 gallons per flush, a few had volumes significantly less than the standard.
Testing included gravity, pressure-assisted and vacuum-assisted models, as well as a few special models, such as dual-flush, flapperless and air-assisted units.
The toilets used in the testing are generally available nationwide at large home-improvement centers and plumbing-supply stores, but were selected for their availability on the West Coast because of the involvement of Seattle and Oakland.
The study included toilets ranging in price from $45 to $450, but price was not a factor in performance. There were both high- and low-priced toilets that displayed satisfactory flushing performance, Hill said.
The bottom line: When buying a toilet, consumers may want to consider water savings over time, as well as other features, he said.
Normal maintenance for most toilets includes flapper replacement every three to five years.
Test results showed increases in water use for some toilet models when the original flapper was replaced by a "universal" replacement flapper, such as those widely available in hardware and home centers.
Consumers should use a replacement flapper recommended by the toilet manufacturer or use test results to select models in which flushing volume is not compromised by the use of a "universal" replacement flapper, Hill said.
Which toilet is best?
Any model that does what you want it to do, I guess.