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Based on appearance, it’s easy to think that all toilets are pretty much the same. But a peek under their lids reveals important differences, and recent innovations, that make shopping for this fixture something of a sleuthing exercise. To learn more about the latest toilet technology, options, and upgrades, read on. It will make the hunt for your next bathroom fixture much easier.

Factor in efficiency when deciding the best toilet to buy

The drive to innovate started in 1994, when the 1.6-gallons-per-flush (gpf) mandate went into effect, replacing the 3.5 to 5 gpf that had been the norm. The pressure to save water hasn’t let up. Now there are high-efficiency (HET) and ultra-high-efficiency (UHET) toilets that use a mere 1.28 and 0.8 gpf, respectively. Yet, contrary to what you might expect, flushing efficacy has also gotten better; independent tests show that some UHETs can evacuate up to 800 grams (1.75 pounds) of solids with every flush.

Water usage statistics

To learn more about the latest toilet technology, options, and upgrades, read on. It will make the hunt for your next bathroom fixture much easier.

Toilet Basics

Siphonic or washdown?

A siphonic toilet (shown in the labeled illustration above) has a larger water spot, but its long, narrow trapway can clog. Washdown toilets rarely back up; their short trapways are 4 inches in diameter, nearly twice the size of siphonics’. That said, washdowns have smaller water spots, so “skid marks” are more of an issue.
One piece or two?

A two-piece toilet has a separate tank and bowl, so it’s easier to install than a heavier one-piece with an integral tank and bowl. One-piece toilets have lower profiles—good for smaller bathrooms—and no tank gasket to leak.
Round bowl or elongated?

Round bowls project 25 to 28 inches, saving precious floor space, but elongated bowls, which can project 31 inches, are more comfortable for many.
Gravity-fed or pressure-assist?

Most toilets rely on gravity to flush, but if clogging is a problem, a toilet with a pressure-assist unit may be the solution. It can empty a 1.6-gallon tank with the force of a 51⁄2-gallon flush. These units use no electricity, but they’re noisy and work only in toilets designed for them.
High seat or low?

The typical height is 16 inches, but the Americans with Disabilities Act (ADA) mandates 17 to 19 inches as easier for older or less-able folks.
Types of Toilets

An appealing profile is important, as is the toilet’s flushing technology.

Two-Piece Toilet

One-Piece Toilet

High Tank

Wash-Down Toilet

The Latest Must-Have Features

Dual Flush

It takes less water to get rid of liquid waste than solids. That’s why some toilets let you select the appropriate flush, typically 0.8 gpf for liquids and 1.6 gpf for solids. Simple. The hard part is remembering to use it.
Fully Glazed Trapway

A slick surface minimizes the chances of a clog.
WaterSense certified

Like the Energy Star program for appliances, the EPA’s WaterSense certification makes it easy to find fixtures that use at least 20 percent less water than the 1.6 gallons currently mandated.
High MaP test score

Maximum performance (MaP) testing conducted by independent agencies determines how much solid waste a toilet can handle. A rating of 350 to 600 grams for a 1.6-gallon flush is good, although some toilets can handle up to 1,000 grams (2.2 pounds!) using only 1.28 gpf. To find a toilet’s MaP score, go to MaP Testing.
Antimicrobial glaze

Mirror-smooth glazes loaded with antimicrobial ions (typically silver) actively kill 99 percent of the germs that try to grow on them. The toilet basically cleans itself.