Does a dishwasher use less water than washing dishes by hand?

It’s time to save water.

If you’re trying to save money or water by hand washing your dishes instead of running the dishwasher, we’re afraid you’ve got it backwards. Studies show that automatic dishwashers use far less water than human hands scrubbing with soap and water.

We wanted to see for ourselves, so we cooked up a test in which we cleaned dishes by hand and measured how much water we used. Then, we did the same thing with an automatic dishwasher.

The result? When you hand wash, you’re using 3.5 times as much water as a dishwasher uses. That’s not even counting the energy used to heat hot water, or the time you could spend doing something else.

Here’s why hand washing is so wasteful.

Here’s how the test went down

We started by dirtying four standard place settings with common, representative food stains like dried-on meat residue and baked-on cheese. Then, we picked two common detergents for loosening up the grease and grime: liquid Joy for hand washing, Cascade for the dishwasher.

We installed our top-rated dishwasher—the popular Bosch 800 Series—for Team Dishwasher, and set it to run on a Normal cycle. For Team Handwash, we used two Reviewed.com employees who have each lived in apartments without automatic dishwashers. One cleaned using a basin of soapy water, while the other left the water running during the scrubbing and sponging.

We attached flow meters to measure how much water the faucet and the dishwasher used. And we inspected the dishes afterwards to see how clean they got.

These are the results