Flushing Our Future? Water Efficient and Dual Flush Toilets -by Erin Diamond

Do you or someone you know have the same toilet that was installed 50 years ago?  If so, you are using up to 7 gallons every time you flush – more than the average person uses in a whole day in many developing countries!  Chances are, though, that your toilet is a little newer than that.  Back in the 90’s the EPA required all new toilets to utilize no more than 1.6 gallons per flush (gpf), giving way to a whole era of poorly performing low-flow toilets.  Lingering stigma from these early models lead many people to think that a low flow toilet means more than one flush, increased cleaning, and regular battles with the plunger.  Not the case these days.  Several types of toilets exist now that are both high efficiency and high performance.  We’ll help you distinguish different types and what to look for.

Before we delve into specifics, a good place to start is to look for the WaterSense label.  WaterSense is an EPA-sponsored program that provides third-party laboratory testing to ensure toilets are meeting rigorous standards for performance and efficiency.  Only those that make it through the testing process with good results are eligible for the WaterSense label.  A list of applicable models is also available on the WaterSense website.

In addition to the WaterSense label, another great resource is a regularly updated report on the performance of popular toilet models by Veritec Consulting Inc. and Koeller and Company.  If you want to see how your own toilet rates, all 65 pages of the latest edition from January 2009 is available here.  Veritec and Koeller and Company also have a simpler 10 page rating report on just WaterSense toilets at the same link, if you prefer to choose a toilet from only those options.

Dual Flush

Many manufacturers are now catching on to the toilet trend that has been used in Australia and New Zealand for years – the dual flush.  This toilet has two buttons – one for liquids (a half-flush) and one for solids (full flush).  No more “if it’s yellow let it mellow, if it’s brown flush it down.”  The two flushes take care of your dilemma without the stagnant odors.  So, what to look for in a dual flush model?

1. Trap Size – This refers to the size of the hole the waste has to get through when the toilet is flushed.  Trap sizes can range, but the standard diameter is between 2 1/8″ and 2 1/4.”   Logic would tell us that the larger the trap, the fewer the clogs.  This is often the case… as with the new American Standard Champion  with a 3″ trap, and Caroma toilets with a 4″ trap.   Aaron has ditched his plunger after years of certainty that his Caromas will not clog.   All in all, we’d recommend going with a large trap… unless it’s a Toto.  which brings me to the next point.

2. Flush mechanism – The Toto Aquia is one of the most popular dual flush models on the market today.  Though it has a standard size trap, Toto has perfected (and patented) the physics of their trapway, increasing the velocity of the flush.  These models are the preferred brand for Mike at Black Cat Plumbing here in Portland. According to him, the Totos offer better performance over other brands, meaning fewer callbacks and higher customer satisfaction.  In addition to the flush itself, talk to your salesperson about durability of the interior parts – how sturdy are the components?  How often do they need to be replaced?

3. Water Level – Every dual flush model has a slightly different water level in the bowl.  This may seem like no big deal… and to some it isn’t.  However, what I call the “kerplunk factor” must be taken into account when choosing the correct product for your toiletary needs.  When something with mass falls from a longer distance, the splash is intensified, if you catch my drift.  There also tends to be a larger amount of “debris” on the sides of the bowl when the water level is very low – though the high intensity flush takes care of most of it, there can be some lingering remains.

This Caroma Sydney Smart 305 ranks very high for performance, and has a lower gpf (1.28g for full flush and .8g for half flush). Most dual flush models are 1.6g and .9g

High Efficiency

With water usage reaching epic proportions in this country, many manufacturers are responding to the need for toilets that use less water per flush than the 1.6gpf our national code requires.  There are several models on the market now that are labeled as High Efficiency Toilets, or HET’s, meaning they use at least 20% less water per flush – usually 1.28 or 1.1gpf.  (This category includes the dual flush models, but I have separated those out for differentiation in this post.)  When looking for a single flush toilet that uses as little H2O as possible, many of the same rules apply.  Look for a larger trap, a strong flush, and talk to the salesperson about any problems that each particular model may have.  Again, refer to Veritec and Koeller’s  Maximum Performance (MaP) of WaterSense High-Efficiency Toilet Fixtures (HETs) for specifics on the model that’s right for you.