November 2005

Volume 14, Number 11

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Aquia Dual-Flush Toilet from Toto

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The Toto Aquia dual-flush toilet will reduce water consumption about 20% compared with a standard toilet. (Inset: users push the larger side of the split flush button for a full flush and the smaller side for a light flush.)

Photo: Toto USA

Toto, a leading toilet manufacturer whose toilets have consistently been among the best in terms of flush performance, introduced to North America the Aquia™ Dual-Max™ dual-flush toilet in May 2005. While this toilet has been available elsewhere for five or six years and is the most popular toilet in Thailand, where it is manufactured, according to Gunnar Baldwin of Toto, this marks the company’s dual-flush entry in North America. The Aquia uses 1.6 gallons (6.0 liters) of water in the high-flush mode and 0.9 gallons (3.4 liters) in the low-flush mode. The low-volume flush is designed for use with liquid wastes (and paper), while the standard flush is for solid wastes.

Like most other Toto toilets, the Aquia is a wash-down, gravity-flush toilet. The bowl has steep sides, and 100% of the flush water enters through the toilet bowl rim and exits through a larger-than-average, 2 5⁄8" (67 mm) trapway. By contrast, most U.S. toilets rely on a siphon-jet technology in which much of the flush water enters through the side of the bowl, creating a swirling, siphonic action that pulls—rather than pushes—water and wastes out of the bowl.

As with an increasing number of toilets, the Aquia is flapperless. Instead of a hinge-mounted flapper, which is prone to seal failure and leaking, the toilet has a flush tower. Flushing the toilet lifts the valve seal mechanism, releasing water from the tank. A full-volume flush fully raises the flush-valve seal; a low-volume flush doesn’t raise the mechanism as far up the tower before it quickly reseals the tank.

Instead of a typical flush lever, the Aquia has a dual-button flush actuator integrated in the center of the toilet tank lid (see inset photo). Depressing the larger side of the button produces the full-volume flush; depressing the smaller side results in the water-conserving flush.

Toto estimates that a typical family of four will save approximately 7,000 gallons (26,000 l) per year by installing this toilet in place of a standard 1.6 gallon-per-flush (gpf) toilet. (The savings will be far higher if it replaces an older toilet.) The elongated bowl complies with building codes for commercial building, allowing the toilet to be used in commercial settings where gravity-flush toilets are used. According to Toto, the Aquia qualifies for Seattle, Washington’s multifamily and commercial-building toilet rebate program as well as for Portland, Oregon’s toilet rebate program.

The Aquia performed very well in the Veritec Consulting, Inc., MaP testing, which is becoming standard throughout the industry (see EBN Vol. 13, No. 1). At full flush, the toilet flushed 800 grams of test media. (Flushing 250 grams is considered the minimum satisfactory performance, and BuildingGreen maintains a minimum threshold of 400 grams for inclusion of a 1.6 gpf toilet in the GreenSpec product directory.)

The toilet seat is slightly taller than normal, but not high enough to qualify as an ADA (Americans with Disabilities Act) toilet. “We’re working on that,” says Baldwin.

The Toto Aquia has a manufacturer’s suggested selling price of $395 to just under $600, depending on color and other options (such as Toto’s SoftClose® seat). The toilet is available in cotton white, colonial white, Sedona beige, bone, gray, and black. The skirted bowl design is touted by Toto as both stylish and easy to maintain.

According to Baldwin, the toilet has been so popular that Toto is having trouble keeping up with demand. When the Aquia was formally rolled out at the Kitchen & Bath Show in May, more than 1,000 were ordered on the first day, says Baldwin, and the current wait for delivery is about two months.

As for user satisfaction, early reports are encouraging. Dave Broustis, who works for the Resource Conservation Division of Seattle Public Utilities, installed an Aquia toilet in his home when it became available. He told EBN that he wasn’t expecting to like it—he had installed a dual-flush toilet before that he didn’t like—but he was pleasantly surprised. “It’s actually great,” he says. Though the water spot (the surface area of the standing water in the bowl) is smaller than that of a typical American toilet, “it does clean the bowl well,” he says. Broustis, who is knowledgeable about toilets through his work for Seattle, explained that wash-down toilets typically do a very good job at flushing solids (“they’re impossible to clog”), but they don’t clean the bowl well because of the smaller water spot. Toto seems to have found a good balance with this product.

– AW

For more information:

Toto USA, Inc.

Morrow, Georgia


Veritec Consulting, Inc.

Mississauga, Ontario


(click on “reports” to download

latest MaP test results)

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