Bath fixtures—toilets, showerheads, and faucets—are one of the easiest places in the home to make an immediate impact on water efficiency. While low-flow fixtures, particularly toilets, got a bad rap when first unveiled two decades ago, engineering has caught up with regulations and demand while the introduction of the WaterSense program now allows consumers to make the switch with confidence.

Unlike certification programs that only consider a single attribute, WaterSense is lauded among green building circles for its more inclusive requirements. Toilets, showerheads, and lav faucets meeting the criteria are not only certified to offer flows 20% lower than federal requirements, but also to perform up to consumers’ expectations.

With options at every price point offering both lower flows and a satisfying experience, there is simply no excuse not to specify water-efficient fixtures for new or remodeled homes. The challenge, of course, remains convincing clients that this isn’t their grandmother’s bath fixture.


By far, the commode has faced the most skepticism from consumers. And for good reason—most homeowners have had bad experiences in the past. When the government lowered flow maximums from 3.5 gpf to 1.6 in 1992, it did so with no input from the industry, says Barbara Higgens, executive director of Plumbing Manufacturers International (PMI). So consumers were left with models that required multiple flushes—and with very little trust in the term “low flow.”

“It’s a mundane product that we all have … but they are actually highly engineered, particularly tank-type toilets because the only energy you have to work with is the potential energy of the water in the tank,” says Rob Zimmerman, manager of engineering, water conservation, and sustainability for Kohler. “The trick is to get that water out of the tank, through to wash the bowl, down into the trap to push waste out with as little amount of turbulence as you can.”

In the years since, manufacturers have used modeling and testing to re-engineer their toilets to help move waste more effectively with less water. The result are units that not only perform well at federal-standard levels, but can now go as low as 1.28, 1.0, or, in the case of Niagara’s new Stealth model, 0.8 gpf.

Further advancing the cause was the introduction of the EPA’s WaterSense standard, which provides third-party assurance that high-efficiency toilets (HETs) use 1.28 gallons or less per flush or that dual-flush toilets, which offer separate flushing options for liquid and solid waste, average 1.28 gpf.

But most important to users, WaterSense-qualified toilets also must be able to dispose of solid waste of 350 grams or more in a single flush in four of five attempts.

Methods for meeting lower flows vary. Pressure-assist mechanisms were some of the first and most reliable options for adding oomph to the flush, but now that suppliers have had time to re-work entire systems, many traditional flush mechanisms work just as well.

“One thing that’s happened is manufacturers have become better and more expert at forming the bowls—shaping the trapways, using comparative modeling techniques to understand water flows,” says Gerber senior product manager Michael Rosen. “That’s helped a lot.”

Among the strategies are smoother bowls and adjusted shapes and inlets to reduce friction points, tanks with larger openings or other re-engineered mechanisms to get the water out faster, and altered flow paths to move water and waste more effectively and help keep the bowl clean. Fired-in glazes also aim to help reduce streaks and bacteria.

WaterSense-labeled toilets require no special installation or changes to the home’s plumbing (although builders should educate homeowners about how to use dual-flush units). Though some wonder if low-flow toilets could reduce force enough to clog home or sewer system drains, representatives from the International Association of Plumbing and Mechanical Officials say that the code-required 2% slope is adequate.