Mold in Your Washing Machine: The Mystery & the Menace

Nancy Williams never wanted to be in a relationship with her washing machine. Ever since she got a fancy front-loader, she’s come to realize just how high-maintenance an appliance can be. “It’s like a pet in the family,” Williams says. “It requires so much more attention than I’m used to.”

First it developed what she describes as “a funky smell—like a sour smell.” Then her clean laundry started picking up the foul odor. By the second year, Williams noticed black slime spreading in the detergent dispenser and along the rubber door gasket. “Textbook mold,” she says.

To fend off the fungus, Williams tasks herself with certain steps manufacturers recommend that go beyond the chore of doing laundry. She occasionally cleans the detergent dispenser, regularly wipes down the door gasket, and keeps the door ajar between loads to air out the wash drum. Still, it comes. “I do a little to try to remove the mold, best I can,” she says. “I’ve resigned myself I can’t keep it away without lots of effort.”

Williams, a university administrator who lives in Asheville, N.C., isn’t the only one who has become fed up with her front-load washer because of mold, odors, and, in some cases, ruined laundry. Consumer complaints go back two decades and aren’t limited to any one brand. Five appliance manufacturers have settled class-action lawsuits over mold-related problems covering roughly 11.5 million front-loaders—almost the number of machines shipped in the last five years—though they did not admit any wrongdoing. Over the years they’ve continually added to the user’s maintenance responsibilities in instruction manuals and more recently amended their products’ terms of use to severely limit consumers’ right to sue.

Some in the appliance industry see moldy front-loaders largely as a thing of the past. “It was an industry issue for a decade, and LG has been aggressively redesigning over that time,” says John Taylor, LG’s senior vice president of public affairs. “So it’s much less of an issue now,” he says.

Perhaps, but for plenty of owners mold is still a very real concern—especially now that people are spending more time at home in close proximity to their appliances due to the coronavirus pandemic. Consumer Reports doesn’t test for mold in our washing machine lab (there are too many variables that could foster mold, from the room’s humidity and airflow to consumer habits, such as washing in cold water), but it does show up consistently in our member surveys. Indeed, 17 percent of people who own a front-load washer say it had mold or mildew, compared with just 3 percent of those who own top-load washers. That’s according to a survey of 94,473 CR members who bought a new washing machine between 2009 and 2019; the problem rate for front-loaders has held fairly steady since we started asking members about mold in 2014.

As a class, front-load washers have been marketed as innovative, stylish, and efficient, with some selling for as much as $2,000. They’re also the highest-performing machines in CR’s tests. The popularity of front-loaders has been part of a trend of laundry machines migrating out of the basement and into dedicated laundry rooms on upper floors. But some have brought with them a messy downside that runs counter to the primary function of the device itself. As Williams says, “If you have to clean the cleaner, I’m thinking that’s a problem.”

Over the years, manufacturers have made design changes to their front-loaders by tilting the washer drum, adding holes to the door gasket, and installing catches to keep the door ajar—all efforts to drain water and allow moisture to evaporate. The latest attempt at a fix comes from GE Appliances. It recently rolled out its new UltraFresh line of front-loaders, which claims to eliminate the maintenance steps of wiping down the gasket and leaving the door ajar. “Take your washer from funky to fresh,” promises the tagline.

But after years of consumer complaints and lawsuits, as well as evolving guidance and technical tweaks from manufacturers, the inevitable question arises: Can anything really be done to stop mold and other microbes from growing in a type of machine that may be inherently prone to promoting it?

Podcast: CR's History With Washer Mold & One Owner's Frustrations

In this podcast, listen to reporter Kimberly Janeway detail her decade-plus exploration of the mold mystery and Nancy Williams describe her front-loading washer frustrations. 


Tiny Spores, Big Headaches

Mold is a tricky problem to pin down. The source can be difficult to identify, and mold is notoriously hard to get rid of. It can also be more than a mere nuisance for people who are allergic to it. “Mold that grows in washing machines can be problematic even when the machine is not in use,” says Melanie Carver, a spokesperson for the Asthma and Allergy Foundation of America. “Mold can trigger allergic symptoms—including sneezing, itching, runny nose, and congestion—and can also be an irritant to the airways.”

Molds and bacteria can occur together, though their odor may help you tell them apart in the laundry room. “Some molds and bacteria produce and release microbial VOCs [volatile organic compounds]—it depends on the species,” says De-Wei Li, Ph.D., a research mycologist for the state of Connecticut. “The stinky smell is often from bacteria, and musty smell is from molds.”

But how does mold find its way into your washing machine in the first place? It very well may have started with you—or on you. Mold spores can be found almost anywhere, indoors and out, and you and your clothing are a movable feast.

“Dirty laundry is a major source of mold spores in the washer,” says Li, who conducted lab work on washer mold earlier in his career. “You wear the clothes, do your routine, and bits of food, soil, and airborne fungi can land on your clothes.”

Into the washer the dirty laundry goes, along with all its microscopic spores. Residual detergent or fabric softener, leftover lint, pocketed tissues, matted hair, and any other organic material can provide the necessary food source. Add the all-important ingredient of lingering moisture, and before long mold can flourish in the intricate folds of the door gasket, spread among the compartments of the detergent dispenser, or develop in the void between the wash tub and the outer tub that encases it. The front-loader presents a moist, friendly environment for mold and bacteria to grow.

“Residual moisture left behind after the wash cycle is the biggest contributor to odor-causing bacteria in front-loaders,” says Ken Rudolph, senior director of product management for clothes care at GE. “The front-loader is a closed system. The gasket seals it and the water and moisture stay in, unlike top-loaders.”

That’s why manufacturers recommend leaving the door open or ajar between loads—and why it’s significant that GE claims consumers can skip that step with its new UltraFresh vent system. “Maintenance steps are important, but not everybody has time to read the manual,” says Rudolph. “What we learned in our research—most weren’t doing it or weren’t aware.”

(For this article, CR also asked for interviews on the subject of mold in front-loaders with Bosch, Electrolux, Kenmore, Samsung, and Whirlpool, all of whom either declined or did not respond to our specific questions.)

But mold doesn’t just love to hide out where the water pools. “One issue is the front-loader’s outer tub, which you don’t see and can’t access,” says Jim Nanni, who’s been overseeing testing of major appliances at CR for 15 years. “In a top-loader, the outer containment tub is often filled with water, in some cases almost to the top. Front-load washers might have a few inches of water at the bottom of the outer tub. But the whole tub isn’t submerged in water, so lint, dirt, and residue from detergents and fabric softeners can build up near the top from the spray of the spinning inner tub.”

More food for mold.

A Move to the Front

CR first reviewed a front-loading washer in the March 1940 issue of Consumers Union Reports magazine. The Bendix Model S was “almost entirely automatic” and, as our tests found, good at cleaning and gentle on fabrics. We also noted that the machine vibrated so much that it had to be bolted to the floor. It sold for $149.50, a premium price at the time—about $2,755 in today’s dollars.

The rise of the modern front-loader dates back to the 1990s, when manufacturers were facing new efficiency standards set by the Department of Energy. Compact front-loaders were already popular in Europe, but manufacturers needed to adapt the design for the U.S. market.

Dave Modtland, a former engineer at Frigidaire, led the team that brought a pioneering front-loader to the U.S. market. He remembers the challenge well. “In Europe, their laundry appliances are in kitchens, but in the U.S they were in basements and later in laundry rooms,” Modtland says. “Americans wanted to do bigger loads all at once, instead of smaller loads more frequently.”

In 1997, CR tested the Frigidaire FWT445GE front-loader developed by Modtland's team. We found that the $800 washer was superb, earning top ratings in washing, as well as for water and energy efficiency. The $1,100 Maytag Neptune front-loader came out that same year, and though CR’s tests revealed that it was mediocre at cleaning, it was also far more efficient than any of the 25 top-loaders we tested. However, front-loaders didn’t catch on right away.

“The price was a factor, as consumers were asked to pay two to three times what they would spend on an agitator top-loader,” says Mark Allwood, a CR senior market analyst who has covered the laundry appliance industry for two decades. “Americans were unfamiliar with front-loaders and the technology behind them, plus it would take a few years before any styling was added to these white boxes.”

The market needed a boost. As part of the Energy Star program, the DOE and Maytag teamed up to generate some real-world data—and publicity—about the superior efficiency and cleaning performance of this newfangled machine. They selected a rural area that included the town of Bern, Kan., population 200, which suffered periodic water shortages due to spotty ground-well production. More than 100 residents agreed to let the DOE collect data on their existing washers and compare it against new Neptune front-loaders, which were given to participants compliments of Maytag.

Based on more than 20,000 loads of laundry, the DOE study showed that the front-loaders cut water consumption by more than one third, from an average of 41 gallons to around 26 gallons per load. Energy consumption dropped by a whopping 58 percent.

Lori Baumgartner was part of the study and has fond memories of her Neptune. “I loved it, it was great, and it saved a lot of water,” says Baumgartner. “It was a lot quieter than my [agitator top-loader]. When it spun out, there wasn’t much moisture in the laundry, so it dried quicker.”

Her only complaint?

“Mold,” she says. “I had to clean out the rubber part with bleach. I learned to keep the door open between loads. If there’s a little bit of moisture, that’s where I noticed mold growing.”

Not everyone from the study we tracked down contended with mold or mildew in their Neptune. Linda Creed says she almost never kept the door open and yet never had mold.

“Some people did have a problem with the rubber part becoming moldy, but I’m a farmer’s wife, and I was doing a lot of whites,” she says, meaning T-shirts and underwear. “And I used hot water and Clorox bleach once a week.” Creed says she figured out, after talking with others in the community, that this might help prevent washer mold—not to mention remove stains from ground-in dirt and truck grease. 

The New Normal

Over time, sales of front-loaders increased. By 2009 they made up 38 percent of the washing machine market, according to shipment data from the Association of Home Appliance Manufacturers (AHAM). And as more manufacturers got into the U.S. front-loader business, including LG and Samsung, major retailers gave them additional floor space, where they stood in dazzling contrast to the boxy white top-loaders.

Front-loaders became more feature-rich, driven by technology and sophisticated sensors. Many of these washers could calibrate just how much water and detergent a load needed, and they had specialty cycles meant for jeans, bedding, and more.

The design of the front-loader is intended to minimize water usage and gently tumble clothes clean with concentrated detergent and minimal suds. “The tub rotates like a Ferris wheel through a puddle of water at the bottom and lifts the laundry up toward the top so that it can splash down into the water,” says Richard Handel, lead tester of laundry appliances for CR. “That action forces the concentrated detergent solution to flow through the fabrics.” Then the high-speed spin cycle extracts much of the water, cutting dryer time and saving more energy.

As front-loaders got more sophisticated, they became even more efficient in response to the DOE’s ever-more-stringent standards. And as the machines evolved, they changed the way Americans wash their clothes. One big shift was away from hot water. “Heating the water requires more energy than running a washer’s motor,” says CR’s Nanni.

In fact, the “normal” settings on high-efficiency washing machines—including front-loaders and HE top-loaders—default to temperatures 15 to 20 degrees cooler than traditional top-loaders from the 1990s, according to Laura Goodman, a senior scientist in fabric care at Procter & Gamble. P&G is the largest seller of detergents in the U.S., and according to its data, between 1996 and 2015 the percentage of cold-water loads in U.S. households increased from 30 to 48 percent.

As wash cycles got cooler, the chemistry of detergents had to change in order for them to clean effectively.

Cold water may clean clothes with these detergents, but it doesn’t kill mold and other microbes. “Hot water can suppress the growth of fungi and even kill some of them, depending on the temperature and duration,” Li says. To help compensate, many washers now offer a “tub clean” cycle, which runs the empty washer on a hot-water setting to clean the tub of residue. (Some recommend using bleach or a tub-cleaning product such as Affresh during the cycle.) According to LG’s Taylor, the company recommends running the tub-clean cycle every 30 loads. But not all machines automatically remind users to run this cycle.

What’s It Going to Take?

The upshot is that the job of keeping mold at bay falls largely to the consumer. Manufacturers instruct owners of front-loaders not to use too much detergent, to regularly wipe down and clean the gasket, and to leave the door open between loads, among other steps.

“Any appliance that routinely comes in contact with dirt and water is going to require regular cleaning and maintenance,” says James Dickerson, chief scientific officer for Consumer Reports. “However, manufacturers might be asking too much of consumers when it comes to front-load washing machines. These appliances must do a better job of creating an inhospitable environment for mold spores, bacteria, and other microbes to grow.”

Because even an aggressive cleaning strategy may not help. In a 2016 survey of more than 67,000 CR members, we found that when people do take steps to fight mold, it doesn’t guarantee that it won’t develop. Another CR survey in 2018 found that only 30 percent of members who reported incidence of mold said they had been able to eradicate it.

So what explains why mold appears in some front-loaders and not in others? “There are so many factors about both the machine and the environment it’s in that could contribute to mold growth,” says Nanni. “It may be impossible to eliminate the potential for mold through consumer maintenance, or even by manufacturers redesigning the machine itself.”

But for consumers stuck with a stinky, slimy laundry machine, it doesn’t matter exactly how the microbes got there. According to a survey commissioned by GE, half of all front-loader owners move back to top-loaders because of odors and the maintenance required. By 2019, front-loaders’ slice of the market had fallen to 27 percent of washers shipped to stores, according to AHAM.

And that has an impact beyond the laundry room. “We are concerned about the environmental implications associated with the trend away from more energy- and water-efficient front-loaders,” says Ann Bailey, products program manager for Energy Star.

Still a Lot to Like

If it weren’t for the mold, the front-load washer design offers a lot of advantages. The washing performance is typically superb: The majority of front-load washers in CR’s rankings earn an Excellent rating in our washing performance test, and they dominate our list of recommended models. “As a class, they outperform both high-efficiency and agitator top-loaders in our tests,” says Handel. “Front-loaders are typically gentler on fabrics, while using less water and extracting more of it.” Front-loaders are also quieter than top-loaders, and when space is tight, most can be stacked with their matching dryer. Prices have come down, too.

And thanks to the DOE standards, all types of washing machines are far more efficient than that pioneering Frigidaire. Today, according to data from CR’s labs, the average top-load agitator uses 20 gallons of water per load, and the average front-loader uses 10. That’s down from almost 43 gallons for a top-loader 25 years ago.

“Back in the 1990s, nobody predicted that we'd see the efficiency improvements in both top- and front-loaders that have occurred," says Andrew deLaski of the Appliance Standards Awareness Project.

Today, the advantages of front-loaders may not make up for the trade-offs, and at least one manufacturer has started warning consumers about them. Samsung spells out on its website that “one of the biggest complaints about front-loading washers is that over time mold can build up around the door’s rubber gasket. To combat this, front-loading washers require a lot more maintenance than top-loading washers.”

For people like Nancy Williams, it’s all a bit too much when you’re just trying to get your clothes clean. After her first front-loader died, she went to complain about the mold at the store where she bought it and walked away with a new front-loader at half price. Second chances and all that.

But the satisfaction of getting a deal was quickly overshadowed—by more creeping black slime. The brand-new washer developed mold and odors, too. And now she’s done. “I’ll ride out this machine until I can’t take it anymore,” Williams says. “Then I’ll replace it with an old-fashioned machine that I don’t have to pamper.”

Editor's Note: A version of this article appeared in the May 2020 issue of Consumer Reports magazine.

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