Competition drives acceptance of high-efficiency toilets in the industry and marketplace.

Flushing performance of HETs is good and getting better. Photo courtesy of Niagara Conservation.


More than 70 percent of plumbing engineers specify high-efficiency toilets when they design water distribution systems, according to an exclusive survey conducted in November 2009 by PM’s sister publication, PM Engineer.

“It’s not surprising,” says Aron Simons, Briggs Industries’ marketing and customer service manager. “We’re all making good products.”

Plumbing contractor Nick Marine agrees: “These toilets really do work. I tried them in my own home first. I changed all five of my toilets.”

Marine, who owns Marine Plumbing in Marietta, Ga., says about 95 percent of the toilets he installs today are HET models. A member of GreenPlumbers USA and Plumbing-Heating-Cooling Contractors – National Association, he recently installed American Standard HETs and other water-saving products in 21 homes in the Atlanta area.

Frequency HETs are Specified

HET Facts

The first HETs were dual-flush (for liquids or solids) models that appeared in the U.S. market in 1994. Today, several water closet manufacturers produce nearly 100 low-flush or dual-flush HET models. Typically, the dual-flush units dispense 0.8 gallons to flush liquid waste and 1.6 gallons to flush solid waste.

All HETs meet the performance requirements outlined in ASME A.112.19.2, which is to flush at a maximum of 1.28 gpf while achieving a MaP test score of removing at least 350 grams of waste. At 1.28 gpf, HETs use 20 percent less water than the 1.6-gpf water closet, which represents a 50 percent reduction of water usage from the 3.5 gallons previously used in toilet design.

The 1992 Federal EPAct mandated that, as of Jan. 1, 1997, the majority of all water closets manufactured for sale in the United States be designed to flush using no more than 1.6 gpf. Toilets account for about 30 percent of indoor water use in the home, according to the EPA.

The EPA’s WaterSense program, which began in June 2006, considers HETs to be “water friendly.” The agency estimates that if WaterSense-labeled HETs replaced all inefficient toilets, the United States would save nearly 2 billion gallons of water per day.

Type of Project in Which HETs are Specified

What's Different This Time

Government-mandated low-flow toilets stirred a swirl of controversy in the 1990s. Flushing and bowl-clearing issues with several of the 1.6-gpf models created headaches for consumers, manufacturers and plumbing contractors.

When PM Engineer surveyed its readers, however, their positive acceptance of HETs surprised even the editors of the magazine. Of the more than 70 percent who specify HETs, nearly half (48 percent) say they specify them most of the time while another 29 percent say they always do.

The survey asks engineers about a number of HET performance factors. More than 80 percent of respondents say these factors are important: flushing performance; bowl clearing; and drainline carry.

“People are paying attention to performance,” says Derek Kirkpatrick, Caroma’s North America general manager. “These models offer conservation without compromise. No double flushing means no environmental impact. HETs are becoming mainstream.”

Paul Kwiat, director of wholesale business for Niagara Conservation, agrees: “It’s a wonderful product going on the market today.” Niagara has introduced a single-flush HET that uses 0.8 gpf.

Significance of HETs as a Way to Gain Green Building Certification

Manufacturers identify better performance as just one reason why HETs are being accepted more quickly than their low-flow forefathers. Others include: the government’s different approach with HETs; standardized testing of the newer models; and a marketplace that’s better educated about the environment.

Rather than forcing the public to use HETs, the U.S. EPA created the WaterSense program, which lists toilets that have earned the WaterSense label through testing. Consumers can choose to purchase 1.6-gpf models or the more water-efficient HETs.

“Government is taking a better role this time around by driving the competition,” Briggs’ Simons says. “Before it was mandated, and the government realizes now that is no way to drive demand. The EPA creating an aspirational group like WaterSense has meant everything is working better.”

Niagara’s Kwiat notes: “Our government has done a real great job with EPA’s WaterSense. Most water utilities have a link to WaterSense’s Web site, and every HET approved in the United States is on there. It’s so easy to get the model and number. It’s a real testimony to what the government has done.”

Caroma’s Kirkpatrick compares the WaterSense label on an HET to a vehicle sticker on a new car that shows miles per gallon.

“The WaterSense label validates what you’re putting in,” he says. “It raises the bar for everyone and promotes accountability. As a manufacturer, you have to answer the call of your critics because it puts you front and center. It says, ‘Fix it or get out.’

“WaterSense is for the betterment of consumers and the environment.”

Types of Water Conservation Measures Implemented

Standardized Tests

Hand in hand with WaterSense is standardized testing manufacturers use to certify their models. The MaP tests utilize miso - a paste made from bean curd - that replaces various media manufacturers had flushed to demonstrate their toilets’ bowl-clearing capabilities.

“With the miso testing in place, we’re all using the same media now,” Simons says. “There’s a common measuring stick, which makes it very easy to compare different models. It’s no longer a matter of us claiming how many golf balls we can flush.”

Consumer publications and Web sites - along with toilet manufacturers - have widely reported MaP test scores. As a result, the shift to HETs hasn’t caused the public fuss that the change to low-flow fixtures did in the 1990s.

“Back then, it appeared to be a dramatic change for people to go from 5 or 3.5 gpf to 1.6,” Kwiat says. “The generations that have grown up since then are far more cognizant of water efficiency and everything we do to conserve our resources. It seems like a natural progression to them.”

The PM Engineer survey asked engineers if there are certain brands of HETs that they wouldn’t specify based on their knowledge of the brands’ flushing performance. A majority (56 percent) say, “No.” Engineers indicate flushing performance of HETs is good and getting better.

Plumbing contractor Marine says most of his customers call him after visiting Web sites to find out about rebates on HETs. In Cobb County, Ga., for example, consumers receive a $50 or $100 credit on their next water bill if they install a low-flow toilet or HET.

“They then ask if the HETs really work,” Marine says. “I tell them that if the toilets are installed correctly by a licensed plumber, they perform well.”

As with any plumbing product, improper installation by unqualified installers can lead to problems, Marine says. For example, the fixture must be set on the floor correctly.

Consumers and plumbing contractors should be aware of another installation issue with HETs that has nothing to do with their performance, Marine says. He informs his customers that the HET tanks are smaller than the ones on 3.5 gpf models, and they might have to touch up the paint behind the tank after installation.