The Great Dish-Cleaning Debate: Dishwasher vs. Washing by Hand

I’ll never forget my grad school days when I’d moved in with a random dude who had rented me a room through Craigslist. I had finished eating dinner on my first night there and began washing my plate and fork in the sink. That’s when he freaked.

He was adamant that all dishes had to go in the dishwasher for sanitizing. I was shocked because I’d just spent the day scrubbing grime from his disgusting kitchen. Anyway, turns out he wasn’t wrong — about this one thing. The dishwasher does in fact clean the dishes “more.”

“Dishwashing is very effective in sanitizing dishes and other household items,” says Dirk Sappok, Director of Product Development at Miele. “It achieves optimal removal of soiling and bacterial matter through a combination of temperature, water distribution, and time — something that’s not possible with hand-washing.”

An Energy Star-certified dishwasher will get the water temp to at least 140°F (60°C). That temperature in the sink would scald your tender mitts. And while you could wear rubber mitts to get the job done, most water heaters nowadays are capped at 120°F (48°C). To actually sanitize dishes, the National Sanitization Foundation (NSF) says our home dishwashers need to reach a final rinse cycle of at least 150°F (65°C).

Basically, the water inside most of our machines gets hotter than the water from our tap, offering a better chance at killing germs.

My mom grew up in rural North Dakota without running water. She and her family members had to carry the water in a cream can from their well, heat it on the stove, and then use that same water to wash all the dishes for a family of seven. And no rinsing.

“By the time we got to the pots and pans,” she says, “the water was pretty gross.” Afterward, they hauled the mess out to a pig trough.

Back then, I guarantee you she wasn’t using more water than a dishwasher. And most of the energy came from good old-fashioned muscle and elbow grease. (Although that stove was coal-burning, but I digress.)

Nowadays, when we hand-wash the dishes, we aren’t exactly following my mom’s same painstaking method. We typically use too much soap and way more water than necessary — using the sprayer and the water pressure to rinse. Or is that just me?

Analysis out of UCLA shows that hand-washing uses more water per dish and per load than packing the dishwasher.

That same analysis shows that dishwashers generate fewer greenhouse gas emissions. The additional water distribution and energy required to heat the water for hand-washing is just a little bit harder on the environment.

A small laboratory study out of the University of Michigan’s School for Environment and Sustainability backs up that info. The study compared typical hand-washing practices to typical machine use.

So if you were to wash 4 loads of dishes per week with 8 place settings per load over the course of 10 years, using the dishwasher would generate less than half of the greenhouse gas emissions as hand-washing would.

So far, the dishwasher method has a two-point lead by being generally more hygienic and also better for the environment. So… that brings us to the question: Should you rinse the dishes before they go into the dishwasher?

“I hand-wash the dishes and then put them in,” says Nathan Wahl, “because that is what I am told to do.” Wahl’s household might be taking things to the extreme. But of people who use dishwashers, more than 90 percent do some level of rinsing before loading.

Consumer Reports says pre-rinsing is a no-no — unless your dishwasher is totally ancient. Machines sold in the last decade have a soil sensor to check for debris and cloudy water. So, if you’ve given your dishes a pre-rinse, your dishwasher thinks it can slack off. And that can leave your dishes with stuck-on food and stains. Plus, you’re wasting water, not to mention your time.

Additionally, “pre-rinsing actually negatively impacts the machine’s performance,” Sappok says. “It takes away the build-up that the detergent enzymes cling to.”

If you didn’t make it into the clean plate club, most manufacturers nowadays recommend scraping leftover chunks into your trash bin or garbage disposal and then loading up your dishwasher. But if you want extra credit, do that scrape into the compost bin, eh?

Greg Gramza says he doesn’t have a dishwasher. “I am fine with just washing dishes by hand,” he says. “But I accidentally broke my wife’s favorite mug this morning when it slipped out of my hand.” (I’m not sure if that last part was on the record.)

Other people prefer hand-washing for the experience. “For me, dishwashing is a meditative act,” Michael Mann says. “I like the feel of the hot water and the dishes in my hands.”

Another close pal of mine doesn’t seem to know what a dishwasher is used for. “We wash by hand and use the dishwasher as a drying rack,” Nimrod Gutman says. May I suggest reading the manual, my friend?

And, of course, you may not have full confidence that some items are dishwasher-friendly. Raise your hand if you’ve seen a manufacturer’s recommendations to hand-wash fancy knives or pots and pans.

Obviously, hand-washing is completely okay! You aren’t breaking any rules by scrubbing your dishes. Sure, that method may not fully sanitize your paring knife so you could, say, perform an operation with it. But let’s hope you weren’t doing that anyway.

And if you live alone and you have a rotation of the same three to four dishes each day, using a dishwasher might not even make sense – unless you don’t mind using it sporadically.

Rest assured: hot water and soap in the sink will still do an adequate job of battling germs and other nasties. And, don’t worry, you’re not going to single-handedly ruin the environment or anything by using the tap. Just follow some best practices.

Many people are adamant users of the dishwasher. (Like my old roommate from Craigslist with that grimy kitchen.)

“We use the dishwasher,” says Kate Ashford Carpenter, “because as a family of four, it would take forever — and far more water — to hand-wash everything.”

“I put everything in the dishwasher,” says Lori Ann Listopad.

And of course, you can follow some best practices for using the dishwasher too.

So, it seems we’ve settled the great dish-cleaning debate. Using the dishwasher is a cleaner, more environmentally friendly option than washing by hand. But there are still sensible and practical reasons to do either.

And for the record, best practices do not include emptying the dishwasher only halfway while you’re heating up your lunch (dear, husband) and then complaining when I come along and load it with my dirty dishes.

Remember, my mother couldn’t stop halfway while hauling that cream can.

Jennifer Chesak is a medical journalist, writing instructor, and freelance book editor living in Nashville. When she’s not writing or sticking her nose in a book, she’s usually running trails or futzing with her garden. See more from her on Instagram or Twitter.