Does Using a Dishwasher Actually Save Water?

The Short Answer? Yes

Overhead shot of an open dishwasher

Nick David / Getty Images

These days, most people are conscious of living more sustainably. But when it comes to defining an eco-friendly lifestyle, the details can get a little murky. Recently, we wondered: Does using a dishwasher (instead of handwashing dishes) actually save water?

We turned to the experts to help settle the debate, once and for all. As Hayley Simmons, director of commercial range at kitchen design company Magnet, points out, “It’s estimated that 10 percent of the water we use in the home is used in the kitchen, so it is a great place to start.”

The Short Answer: Yes

Tanya Klien, CEO of Anta Plumbing, says, “Using a dishwasher can save you up to 24 gallons per load as long as you run your dishwasher every night.”

“The facts are that using a dishwasher nightly instead of ten minutes of handwashing can save more than 100 gallons of water weekly,” Klien adds. “That totals more than 5,000 gallons of water annually.”

Morgan Eberhard, senior scientific communications manager with P&G Home Care brands, including Cascade and Dawn, also looks at the stats: “Interestingly, 40 percent of consumers believe the dishwasher uses more water than washing by hand. In reality, you can clean a full dishwasher with the same amount of water used in just two minutes of washing dishes by hand.” 

Your Handwashing Is (Probably) Ineffective

“Handwashing is highly ineffective the way most people do it,” Klien says. “People don’t just use one sinkful of water, but will change out the water and add more hot water to keep it hot. They also must rinse their dishes and tend to keep water running while they do so.”

“The water in a dishwasher is cleaning dishes and utensils at all times with no waste,” adds Jeremy Tompson, strategic cleaning advisor at YouthfulHome, a cleaning services finder. “It also heats the water beyond what a person could stand, which cleans everything more quickly.” 

Handwashing Uses More Water Less Efficiently

According to Klien, “Handwashing can use as much as 27 gallons of water per load, while an energy-saving dishwasher uses only around three gallons.”

Along with using less water, dishwashers also use water more efficiently. As Katie Sadler, Whirlpool kitchen brand manager, explains, “By using your dishwasher, it filters and reuses the water throughout the cycle to minimize the amount of freshwater required.”

This does come with some caveats. “The dishwasher must be Energy Star–certified to get these types of water savings,” notes Klien. “People believe you shouldn’t run a dishwasher if you don’t have a full load or should handwash when there are only a few dishes. Yet, you will still save water even running a less-than-full load over handwashing.”

Tompson agrees, but notes that you don’t need to swap out your machine to save water. 

“Modern energy-efficient dishwashers save the most water (and energy), but even older models can be more efficient than handwashing,” Tompson says. “Environmental groups and academics have measured water usage with similar results. A modern dishwasher uses about four gallons of water compared to 27 gallons when washing the same dishes by hand. Older dishwasher models may use as much as fifteen gallons of water—still less than handwashing.”

Upgrade If and When You Can

Even if older models are still better than handwashing, upgrading your machine to one that’s energy-efficient is a good investment. “One of the best ways to save energy within your kitchen is to invest in smart appliances,” says Simmons. “Although it may cost you initially, you’ll be saving a lot more time, energy, and money in the long run.” 

Even if your older machine is better than handwashing, the math surrounding more energy-efficient machines can’t be ignored. “Energy Star–certified dishwashers use less than four gallons of water in an entire cycle,” says Eberhard. “A running tap uses that same amount of water every two minutes, or essentially in the amount of time it takes to wash only eight dishes, on average. By making the choice to use an Energy Star–certified dishwasher, you can use 80 percent less water than washing dishes at a running sink.” 

And when it comes time to upgrade, size and scale matter. “If your appliance is too big for your needs, then it is still going to waste some serious energy,” Simmons says. “If you live on your own, you’re most likely not going to need a full-size model with a large capacity, so go smaller and save yourself some money and energy.”

No, You Don’t Need to Rinse First

If you live in a house divided on the to rinse or not to rinse debate, Klien is here to bravely settle the score. “Some people will still wash or rinse their dishes before putting them in the dishwasher, but that is unnecessary and a waste of water,” Klien says. “Dishwashers today are highly effective, and skipping the pre-wash step can save thousands of gallons a year. Modern dishwashers need some dishes to be soiled to work effectively, as they have sensors determining how powerful to make the wash.”

“When multiplied by all dishwasher users in the U.S. that pre-wash dishes, skipping it could save up to 150 billion gallons of water each year,” adds Eberhard. “Individual households can save more than 100 gallons of water per week simply by switching up their daily cleaning routines. That’s over 5,000 gallons in a year—equivalent to over 80,000 glasses of water.”

You Can Make Your Dishwasher Even More Efficient

Even if it’s generally agreed that dishwashers are the more sustainable option, Simmons gave us a few ways to maximize their efficiency. “Avoid leaving your dishwasher (or any appliances) on standby or switched on. While understandably some appliances in your home cannot be switched off, such as the fridge-freezer, other appliances are sitting around wasting energy,” Simmons says.  

Treat Your Dishwasher Right

To help prolong the life of your dishwasher, Simmons has a few tips to keep in mind. “This may go without saying, but making sure your dishwasher is clean is a surefire way to help it last that little bit longer,” Simmons says. “It will help it run smoothly, prevent any turn from blocking certain functions, and also keep it looking brand new.”

Running a Full Dishwasher Saves You Time and Money

“If you are preparing at least two meals a day for a family of four, you can save more than 75 percent in energy and water costs by running your dishwasher instead of handwashing your dishes,” says Eberhard. “This can save you more than $100 per year on utility bills just by using your dishwasher and roughly $1,300 over the lifetime of your dishwasher. And as they say, time is money, and using a dishwasher can save you thirty minutes on average. That means you can save nearly ten days of personal time per year by letting your dishwasher do the work instead of handwashing.”

Know Your Machine’s Special Features

“Whirlpool brand's recommendation is to always use a quality detergent to fully optimize the dishwasher’s functions,” notes Sadler. “You should use the normal cycle whenever possible, as this is your most efficient cycle and geared for everyday dish loads. Another tip is to use a delay feature, available on some Whirlpool dishwasher models, which enables you to run your dishwasher during off-peak hours. Local utilities recommend avoiding heavy usage of energy at certain times of the day.”

Clean as You Go—Responsibly

Old habits can be hard to break, notes Eberhard, so if your cleaning method requires some handwashing, do it responsibly.

“Many people find the easiest way to stay on top of your dishes is to use the 'clean as you go' method,” says Eberhard. “For example, cleaning up prep dishes while your meal is still cooking not only saves time but prevents your dishes from piling up in the sink to tackle later. More than 60 percent of people in the U.S. say they clean as they go … but if you’re cleaning as you go, there’s no need to fill up a sink with water. You can just spray, wipe, and rinse to get out of the kitchen faster. Otherwise, we recommended choosing the dishwasher, since eight dishes is all it takes to save water compared to handwashing.”

There Are Some Exceptions

“Certain items shouldn’t be washed in a dishwasher, including wooden items, some plastics, cast iron pans, and sharp knives,” says Tompson. “Knives can be dulled by being washed in a dishwasher.”

Sadler agrees, noting that handwashing certain items is just as much about protecting your kitchenware as it is about prolonging the life of your machine. “Whirlpool brand recommends that all non-dishwasher-safe items be handwashed. Additionally, our recommendation is to handwash nonstick cookware, as well as kitchen knives, fine china, crystal, and anything wooden, cast iron, aluminum, gold, copper, silver, and bronze,” she says. “By hand-washing these types of cookware, you’re avoiding causing damage to the dishwasher, as well as any potential harm to the item’s finish.”

Article Sources
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  1. How to Use a Chef's Knife. Institute of Agriculture and Natural Resources. University of Nebraska-Lincoln.