What Happens When Consumer Reports Tests Toilets

Brace yourself—it involves robot poop

5 toilets without a tank lid being tested in a Consumer Reports lab Photo: John Walsh/Consumer Reports

Behind the doors in the maze of labs at CR’s headquarters, testers continuously evaluate a host of appliances and other products to learn which perform best. It’s a little like Willy Wonka’s factory, but for big kids with a taste more for science than sugar.

Fortunately, I don’t need a golden ticket for access since I work here. I just have to ask nicely. First stop: Toilets—a product that many of us take for granted, but that few of us could live without. CR testing engineers Matthew Guayara and John Banta let me observe the swirl of activity that goes into determining whether a toilet is tops. 

CR testing engineer Matthew Guayara is elbow-deep in his fifth toilet of the day.

technician testing toilet while another technician waves behind him

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

Matthew is working with John Banta (in the back) because toilet testing requires two people: Each throne is about as unwieldy and heavy as a full-grown female Rottweiler—or 80 to 100 pounds for you cat people.

CR has been testing toilets since the ’80s and a lot of interesting stuff happens between the time the porcelain bowls roll into the lab to the moment updated ratings are published on our website.

Testers hoist each toilet onto this elevated testing rig.

The toilets are placed over holes cut into the platform. It’s elevated to give testers room to place a bucket and drain pipe under the toilets to catch whatever is flushed out.

2 toilets on testing rig with mirror

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

The angled mirror is left over from the days when CR did toilet testing demonstrations for the public. Alas, people have since discovered Netflix.

The testers then hook up a waterline and fill ’er up to the waterline mark inside the tank. (Make sure your toilets at home are also filling to this waterline mark. If not, they might not be getting enough water to whisk away an entire load.)

water flow meter attached to piping on orange plastic bucket

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

The gadget above is called a flow meter. It measures the volume and flow of water into and out of the toilet. Most water-saving toilets claim to use 1.28 gallons per flush. Banta tells me that most of them use more—like 1.4 or 1.7 gallons—but still way less than the 6 gallons old toilets guzzled.

Testers prepare buckets of simulated waste.

Which looks exactly like you’d imagine robot poop would look (if you imagine such things).

white bucket with orange and green sponges and water filled condom, another bucket with white plastic balls

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

What the heck was this robot eating?

orange and green sponges with metal screws in them

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

A combination of damp natural and synthetic sponges, some weighted with metal screws, mimic floaters. "The different size screws are intended to cause the sponges to float at different levels in the water,” says Jim Nanni, CR’s director of appliance testing, who developed these tests based on scientific studies that looked at artificial fecal matter with high clog potential.

toilet being flushed with sponges, water filled condom, and white plastic balls

GIF: Perry Santanachote/Consumer Reports GIF: Perry Santanachote/Consumer Reports

The shape, density, and size of the polyethylene balls remind me of constipated poop. (That’s one very relieved robot!)

technician tying condom filled with water

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

Water filled condoms stand in for a soft, easy stool. They’re not lubricated (don’t want to make it too easy to slip through).

Testers conduct three solid-waste tests on each toilet: easy, intermediate, and difficult.

technician shaking bucket filled with sponges, plastic balls, and water filled condom

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

The difficult dump is a doozy: 160 polyethylene balls, 7 sponges, and 2 water-filled condoms. Banta says few toilets can gobble the difficult load in one go. "That’s how we’re able to get the differentiating data we use to score each toilet," he says.

Testers dump a “difficult” load into the toilet. And then comes the moment of truth . . .

toilet being flushed with sponges, water filled condom, and white plastic balls

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

After one flush, 109 balls, six sponges, and 1 water-filled condom remain. (Testers determine this by counting what’s flushed out.)

After three flushes, we still have 92 balls and 6 sponges hanging around which means we’ve got a clog. How’s this toilet rating so far? Kind of, eh, crappy.

“This is why people should courtesy flush,” Banta says. “Breaking up the load is just common sense.”

hand holding plastic sieve filled with white plastic balls, orange and green sponges, and water filled condoms

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

Don’t worry, we don’t dump our robot poop into the sewer. Those bits and bobs are caught in this sieve with each flush, counted, and then re-used by the testers.

technician plunging clogged toilet during testing

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

When toilets clog, Guayara whips out the plunger. (He says he likes the accordion-style because they pump water and also fit in all types of toilet shapes.)

Testers move the toilet to another rig for the drain line carry test.

Which requires a ride on the lavatory lift.

A toilet being lifted by crank elevator in a Consumer Reports lab

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

This rig is much higher to accommodate the pitch angle of the drain line, which is made of clear plastic piping and wraps 75 feet around the lab, incorporating three elbows and two S-turns.

The pipes are clear so testers can see how well a toilet would move waste from bowl to sewer and whether there’s enough force to make sure nothing gets stuck. A low rating in this test means the toilet might be more prone to clogging your drain pipes.

Testers flush four synthetic sponges down the toilet and we’re off to the races!

3 blue sponges being flushed down toilet for testing

GIF: Perry Santanachote/Consumer Reports GIF: Perry Santanachote/Consumer Reports

Banta measures how far each sponge moves down the tube. (He installed LED lights in the pipes for better visibility, inadvertently adding a Space Odyssey feel to this test.) No sponges make it all the way through on the first flush, which is normal—the test needs to be somewhat more challenging than the plumbing in homes to allow our ratings to be comparative. 

The next tests are more mundane, but no less important.

Testers take some measurements.

technician measuring height of toilet on blue platform

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

Guayara measures the height of each toilet’s seat and notes which ones are compliant with Americans With Disabilities Act guidelines (at least 16 inches high at the seat). We measure with the seat on if the toilet comes with one (did you know that most don’t?). The bum ticklers—we’re talking about bidet seats here, people!—are unfortunately always sold separately.

technician using measuring tape to measure length of water spot in toilet

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

Bowl measurements help gauge soil and odor potential. Dying the water helps testers take accurate and fast measurements. You’ll find this info in the Features & Specs section of each review in our toilet ratings. Deeper and wider = less stink and stick potential because there’s more room for waste to be covered by water, which helps trap odors and prevent messes.

Testers gauge the cleaning power.

technician applying red paint to test toilet

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

Guayara applies acrylic paint in “cottage red” on a dry spot in the bowl and flushes twice to see how much paint is removed. The front of the bowl is the most challenging spot for a toilet to clean, especially with elongated models. “Not all waste is deposited to the rear of the bowl where it’s deep,” Nanni says. “Think of a child teetering off the front edge of the seat or an adult depositing their stomach contents due to illness or a night of drinking.” 

Party potty tip: “If you’re at a party and make a mess of the toilet bowl, just hold down the handle while flushing to keep the water flowing,” Banta says. He adds that a pre-flush before you do your business can save you from embarrassment because poop is less likely to stick to a wet bowl than a dry one.

technician applying marker line during toilet testing

GIF: John Walsh/Consumer Reports GIF: John Walsh/Consumer Reports

Testers also evaluate cleaning ability by drawing a line around the bowl about an inch under the rim with a water-soluble marker. The fewer markings left after flushing, the better a toilet cleans.

Testers measure how loud the flush is.

sound meter on tripod testing sound levels by toilet within wooden walls

Photo: John Walsh/Consumer Reports Photo: John Walsh/Consumer Reports

For this test, they place a decibel meter outside a makeshift doorless plywood stall. Most toilets flush at about 70 to 74 decibels. The ones with pressure assist provide more oomph and more volume: about 85 decibels (louder than a typical vacuum cleaner). They also tend to clog less than conventional models.

Testers use a shop vacuum to empty out all the water in the toilet bowl and tank when testing is finished.

gif of technician vacuuming water from tested toilet

GIF: Perry Santanachote/Consumer Reports GIF: Perry Santanachote/Consumer Reports

What’s Banta’s biggest toilet takeaway after years of testing them? "Brand or price don’t necessarily correlate with performance," he says. Your best bet? Check out our toilet buying guide and ratings before making a purchase. Your plumbing will thank you!


Headshot of Perry Santanachote, editor with the Home editorial team at Consumer Reports

Perry Santanachote

A multidimensional background in lifestyle journalism, recipe development, and anthropology impels me to bring a human element to the coverage of home kitchen appliances. When I'm not researching dishwashers and blenders or poring over market reports, I'm likely immersed in a juicy crossword puzzle or trying (and failing) to love exercise. Find me on Facebook