How Much Water Does a Dishwasher Use?

Why Even Ask?

Dishwashers use water. And fresh, clean water is an extremely limited resource. Yeah I know what you are thinking, and yes the planet is mostly covered in water. But unfortunately, most of that water contains high levels of salt. The only way for us humans to drink that salty water is if it undergoes desalination. This is the process of removing the salt from the water, which I might add, is extremely expensive. And to top it off, this limited resource is heavily impacted with things like droughts, contamination, and wasteful use. So basically, anyone who has easy access to fresh water should take careful steps to limit their water use.

The Why and How of Water Conservation

People should do their best to conserve water for three reasons. 

  1. The less water used or wasted by people, the less clean water will become contaminated. Using excess amounts of water can put strain on septic and sewage systems. Which in turn, can lead to contamination of groundwater. This happens as the untreated, dirty water seeps from the sewage system into the ground.
  2. Water conservation reduces energy use and saves households money. Most families pay to use water in their cities or regions. The less water a household uses, the less they have to pay each period. Appliances that use water, such as washing machines and dishwashers, also use a considerable amount of energy.
  3. Conserving water now allows cities and regions to plan for more efficient use of the water resources in the future. If most of an area's clean water is wasted, there will not be water for future generations to use. This means that the city will need to come up with new ways to produce clean, fresh water, which will ultimately be at your expense (yup, a lose lose. I know.)

History of the Dishwasher

The first dishwasher was invented in America in 1850, by Joel Houghton. The very first dishwasher patent was for a wooden machine with a hand-turned wheel that splashed water on dishes. So basically, it did nothing, but it was the first patent. In 1865 L.A. Alexander obtained a patent for a  device that used a hand crank and gearing to spin a rack of dishes through the dishwater. So this patent did the exact opposite thing the Joel Houghton’s machine did. And you guessed it, it still didn’t really work. 

But then came Josephine Cochrane. In 1886 she invented the very first practical dishwasher. But as with all new inventions, it was received poorly when revealed at the 1893, World' Fair. Only hotels and large restaurants showed any interest in her machine. Cochrane's machine was a hand-operated mechanical dishwasher that worked by passing dirty dishes under jets of hot water by means of a conveyor belt or a revolving basket. And of course, being the first of its kind, it was super inefficient. It was not until the 1950s, that dishwashers caught on with the general public as they became cheaper and a more usable size. And I am sure that electricity made these large machines a bit more appealing.

Environmental Impact of Dishwashers

A study out of the University of Bonn in Germany, reported by Pablo Päster in the May/June issue of EatingWell Magazine, found that washing a load of dishes (12 place settings) by hand uses on average 27 gallons of water and 2.5 kilowatt-hours of energy to heat the water. This energy consumption is equivalent to running a hair dryer for two and a half hours.

By comparison, an energy-efficient dishwasher uses about four gallons of water and 1 kWh of energy per load. Researchers also found that dishwashers cleaned better, as half of the hand-washers failed to reach an “acceptable level” of cleanliness. Due to our hands inability to withstand scalding hot water, which is necessary for proper cleaning.

So as you can see, dishwashers use less water, less energy, and less time. Crazy to think, but that big box under your counter is actually a super energy and time efficient device. You should give it a hug next time you walk by it.

Benefits of Dishwashers

Dishwashers use less energy:

An Energy Star certified dishwasher can use as little as 3 gallons per load, according to the Natural Resources Defense Council. In fact, an Energy Star certified dishwasher can save almost 5,000 gallons of water per year. If your dishwasher was manufactured in or after 2013, it will meet the new standards that require dishwashers to use as little as 5 gallons per load. If that sounds like a lot, units built before 1994 used as much as 10 gallons per load. 

Dishwashers save energy:

Dishwasher require hot water to work. Where does this hot water come from you ask? Well it comes from your (outdated and energy inefficient) water heater. So, less water equals less heating which saves you energy and money. Additionally, most newer dishwashers actually have heaters inside that warm up water more efficiently than your water heater. And when compared to washing dishes by hand, dishwashers use less than half the amount of energy required to wash dishes by hand. Yes, washing dishes by hand requires no electrical input. But don’t forget, it does require the use of hot water. And that hot water comes from your (outdated and energy inefficient) water heater. 

Dishwashers get dishes cleaner:

It takes water that is 140 or 145 degrees Fahrenheit to fully sanitize dishes. And unless you’re superman, your hands can't handle that kind of heat. So, let your dishwasher deal with the high temperatures while you sit back and relax.

Dishwashers are convenient: 

Perhaps the greatest advantage of using a dishwasher is convenience and time savings. The U.S. Department of Energy estimates that using a dishwasher can save you up to 230 hours of personal time each year.

Tips for Using a Dishwasher

Don't rinse by hand:

Rinsing your dishes before you stick them in your dishwasher is majorly wasteful. Pre-rinsing wastes more than 6,000 gallons of water per household every year. In fact, most newer dishwashers can handle bits of food. Don’t worry, your dishes will still come out clean as long as you scrape the big stuff into the trash (or compost pile).

Make sure you have a full load:

All of the savings that I stated only apply to full loads. If you can't seem to fill up your dishwasher once a day, use the rinse and hold feature. This will prevent food from drying and sticking until you get around to starting a load and will still help you be green.

Water Efficient Dishwashers

Let's get some terms down. Non-Energy Star dishwashers use about 6 gallons per wash, while Energy Star dishwashers only consume about 4 gallons per wash. Now that we have that cleared up, let's take a look at some of the best machines on the market. Real quick, it is important to know that price is not everything when it comes to efficiency. As long as it is Energy Star rated, it will still only use 4 gallons and have the same results as a more expensive machine. 

1: KitchenAid KDFE204ESS - $999

Depends on cycle / Normal 2.8 to 7.9 gallons (depending on light, heavy or medium)

kitchenaid dishwasher kdfe204ess

Features

  • 46 dBA Sound Level
  • 6 Cycles / 6 Options
  • Third Level Rack
  • Satin Glide Max Upper Rails
  • Proscrub

2: Jenn-Air TriFecta Series JDB9200CWS - $1,399

Depends on cycle / Normal 2.8 to 7.9 gallons (depending on light, heavy or medium)

jenn-air trfecta series jdb9200cws dishwasher

Features

  • 42 dBA Sound Level
  • 6 Wash Cycles / 5 Options
  • SteamFinish Option
  • Energy Star®
  • Interior LED Theater Lighting

3: Thermador Topaz Series DWHD640JFP - $1,499

Average 2.2 gallons / cycle in Auto Program

thermador topaz series dishwasher dwhd640jfp

Features

  • 44 dBA Sound Level
  • 6 Wash Cycles / 4 Options
  • PowerBoost
  • Sens-A-Wash System
  • Professional Handle
  • Chef's Tool Drawer

4: Bosch 800 DLX Series SHX68TL5UC - $899

Average 2.9 gallons / cycle in Auto Program

Bosch 800 dlx shx68tl5uc dishwasher

Features

  • 44 dBA Sound Level
  • 6 Wash Cycles / 6 Options
  • Adjustable Upper Rack
  • 3rd Top Rack
  • InfoLight

5: Miele Futura Dimension Series G6365SCVISF - $1,499

Average 1.72 gallons / cycle in Auto Program

Miele Futura Dimension Series G6365SCVIS Dishwasher

Features

  • 44 dBA Sound Level
  • 9 Wash Cycles / 3 Wash Options
  • FlexiCare Premium Basket Design
  • 3D Cutlery Tray
  • Water Softening Unit

Conclusion

Believe it or not, but dishwashers are actually more energy efficient, use less water, and are more convenient when compared to washing dishes by hand. Well, I assume that the whole convenience aspect of dishwashers wasn’t really a surprise. Regardless, modern dishwashers which have received an Energy Star rating are considerably better for the environment than hand washing. But, these advantages only apply if the dishwasher is used properly and thoughtfully. Remember to never rinse your dishes prior to putting them into the dishwasher. And make sure that your dishwasher is completely full before you turn it on. And if you do not have a dishwater (like myself), try to limit the amount of water that you use while washing. Be quick and efficient with your washing. As always, if a lot of people do small things big things will happen.

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Tyler Farr
 

Tyler is an energetic nature enthusiast who is currently considering moving into a tiny house. Tyler and his wife enjoy hiking, mountain biking, camping, and doing anything in the great outdoors. He hopes that the articles he writes will help others learn how important it is to take care of the environment.

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