When people look into replicating solid human waste as part of their work, you realize they must take their jobs seriously.

Bill Gauley, principal at Veritec Consulting of Toronto, Canada, and John Koeller, a leading water savings expert and principal at Koeller and Company, Los Angeles, are two dedicated engineers who have been testing toilet performance for a number of years.

Previous toilet trials initiated by the various manufacturers used sponges, plastic balls, golf balls, sawdust and/or construction paper as test media.

On a trip to one manufacturing facility, Mr Gauley and Mr Koeller noticed Japanese toilet manufacturer Toto using soybean paste to test their toilets. Messrs Gauley and Koeller selected this medium to complete their testing because many of its physical properties are similar to solid human waste.

The paste is extruded into four-inch-long cylinders with an oversize caulking gun.
“It is important to simulate the real world in terms of test media used,” Mr Koeller says. “Veritec tests the flush performance of toilets and publish the results, all in the name of water conservation. We want to help consumers save water and be happy with the performance.”

According to the US Environmental Protection Agency, toilets are the largest water use appliance in a typical home. And, Mr Koeller says “municipal water and waste water treatment facilities cost a lot of money, and one way to defer or eliminate plant expansion is to save water by using less volume of water to flush.”

Mr Gauley’s interest in toilets began when he found that toilet models of several manufacturers were flushing with more water than the Code allowed.

“In the US, 6L (11/2 gallons) per flush is the mandated maximum - you can’t sell a toilet if it flushes with greater than 6L,” he says. “But the mindset of many consumers and plumbers in America is that 9 or 10L (21/3 to 21/2 gallons) is required for a good flush and that 6L is just not enough.”

Performance vs water saving

The first toilets in North America that flushed at 6L or less did not always perform that well. Less water meant that there wasn’t enough water with enough power to clear the bowl, which resulted in unhappy customers.

These low-flow toilets with marginal performance encouraged consumers to double flush, use plungers, or get their plumber to illegally modify their toilet to use more water. Mr Gauley points out that most plumbers are more interested in having happy customers than in saving water.

Mr Koeller agrees that customers need to be satisfied with the performance of low-flush toilets. “If a low flush toilet is not performing, then the plumber, homeowner or building maintenance person may tamper with it, and that will reduce water conservation,” he says, “so after tampering, a 6L toilet becomes a 13L (31/2 gallons) flusher. On the other hand, customers satisfied with their toilet’s performance will not tamper with it.”

Performance of 6L toilets has improved significantly since the mid-1990s, however the bad reputation of the early low-flush toilets still exists in Canada and the US and this makes it hard to sell the new high-performance low-flush toilets.

So Mr Gauley moved from flush volume testing to flush performance testing, and his research proves that 6L of water is more than enough to deliver good, or even exceptional, performance.

“Based on the results of extensive performance testing, manufacturers stepped up to the plate and began making far better toilets. While the minimum threshold for providing customer performance satisfaction is set at 250 grams (84/5oz), some models today can flush over 1,000 grams(351/4oz) of waste and can truly be classified as exceptional,” says Mr Gauley.

“Customers can often get $100 or more in water authority rebates for replacing old water-wasting toilets with a 6L flusher.