Low-flush toilets save water, money by the bowlful

May 06, 1994|By Vincent Kiernan | Vincent Kiernan,Technology Review

The common toilet that chugs 3.5 gallons or more with every flush is about to become a relic of our nation's water-wasting past.

Since Jan. 1, it has been illegal in the United States to manufacture the old-style toilets found in almost every home in the nation.

Manufacturers can now make only low-consumption residential toilets that use no more than 1.6 gallons per flush. And, starting in 1997, new toilets for use in business and industry must also be low-flow models.

These requirements are just one part of the Energy Policy Act of 1992, a wide-ranging law intended to promote resource efficiency.

Proponents say the law's toilet provisions will reduce not only the amount of water pumped into new homes but also the wastewater that will need to be treated. A family of four using low-flow toilets, for example, will save a whopping 11,000 gallons of water each year.

Such innovations could make a huge dent in the nation's consumption of both water and energy.

"The flush toilet uses more water than any other fixture or appliance in the typical home," says William Sharpe, a professor of forest hydrology at Pennsylvania State University. "Forty percent of total water use in the average home is for flushing the toilet."

What's more, toilets use drinking water, which must meet strict health standards. In effect, water-guzzling toilets are taking high-quality water and turning it into waste, which then has to be treated to make it clean again.

The law doesn't require homeowners to replace toilets they now have. But because it bans the manufacture of high-flow toilets, homeowners who renovate a bathroom will find only water-stingy models from which to choose.

This provision has set the plumbing industry scurrying to devise new designs that will work well enough so consumers won't feel compelled to flush more than once each time they use the toilet.

Flush toilets have remained pretty much the same since Thomas Crapper, a British engineer, invented them in 1872. The typical design -- known in industry circles as the gravity-assisted model -- relies on water from a storage tank running through the toilet bowl and out a hole in the bottom, creating a siphon that pulls waste along with it out the bowl.

"To make toilets more efficient, most people think you just have to cut back the amount of water in the bowl," says Peter DeMarco, an engineer at American Standard in Piscataway, N.J., one of the nation's largest manufacturers of toilets and other plumbing fixtures.

But when less water is used, the flush loses some of its muscle, and stains frequently remain in the bowl.

That explains why Americans tend to spurn European low-flow toilets, which have been around for years, he says, but which don't meet the white-glove standard.

So U.S. manufacturers have given the gravity-assisted toilet a make-over. To help water flow faster, the bowl has steeper sides and contains less water so the 1.6 gallons flushing down from the tank will have less to push against and will, therefore, flow faster.

Manufacturers have also crafted pressurized toilets that add extra oomph to the water flowing through the bowl.

For example, Kohler Co. of Kohler, Wis., recently unveiled its Trocadero toilet, which incorporates a 0.2-horsepower water pump in the tank.

"It is simply plugged into an outlet in the same way a kitchen garbage disposal is plugged in at the time of installation," says a company spokesperson.

Because the pump runs for only a couple of seconds during each flush, it would cost a family of four about $1 a year in electricity, estimates John Brown, a senior market analyst at Kohler.

By comparison, if the 1.5-gallon toilet were to replace a 3.5-gallon unit, he says, it would save the same family more than 11,000 gallons of water, or about $30, per year.

American Standard's version of the pressure-assisted toilet uses compressed air, stored in a vessel in the water tank, to help whoosh the flushing water on its way. As water fills the water tank, it compresses the air.

When a button on the tank is pushed, the air is released, pushing water and waste through the bottom of the bowl and into the sewer line.

Such models would not only save water but also help water-treatment plants, which generally work more efficiently with the more concentrated waste that low-flow toilets would provide, says Sharpe.

It's for just such reasons that state and local governments in Massachusetts, New York City, and Los Angeles started mandating low-flow toilets long before the federal government got into the act.

Those initiatives -- along with the fact that water isn't scarce everywhere -- have led critics of the new federal standards to complain that Washington is stepping in where it doesn't belong.

"We have plenty of water in certain areas," Ronald Marlenee, then a Republican congressman from Montana, complained to the House of Representatives when the water-conservation provisions were debated in 1992.

Water-conservation rules should be left to local governments, he said. "I cannot believe that in all seriousness we are on the floor of this House establishing toilet police for the United States of America."

But in the long run, federal standards may be the only way to goad manufacturers into large-scale manufacturing of water-efficient toilets.

Without national standards, "we will create a situation where each locality will establish its own standards for energy consumption and water consumption," says Chester Atkins, the former Democratic congressman from Massachusetts who led the fight for water-efficient plumbing.

"That will make it impossible to have a national marketplace."

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