Never add extra water to your washing machine—unless you want dirty clothes

We get one question more than any other: How can my laundry get clean with so little water?

Some people have told us that they are so concerned when they look into the washing machine, they have manually added water to the washing machine. But, unless you want dirtier clothes, this is not the way to go.

Be confident in the fact that your washing machine knows what it’s doing. Modern washers are engineered to use as little water as possible, and it gives you just the right amount of water you need to wash your clothes. In fact, modern washing machines will drain any excess water to protect you from a flooded laundry room, so there's no advantage to adding more.

We did some tests in our Reviewed labs. We compared the cleanliness of clothes washed with more water to the cleanliness of clothes washed with the machine's usual amount of water.

We used top-loading GE GTW685BSLWS, and our testing showed that adding more water to a wash load actually gives you dirtier clothes.

What we did

To test for cleaning power at different water levels, we started with stain strips. These are stained with some of the toughest laundry challenges—blood, red wine, sebum, cocoa, and carbon (to approximate soot and oil stains). We stained some additional fabric using coffee grounds to mimic dirt, and a solution of bright purple dye.

We washed our stained fabrics on separate cycles, using the same amount of detergent for each on the washer's colors setting. But, on one cycle, we added 46% more water.

Here’s what happened

When we compared the two loads, we saw these results:

• The purple dye washed away completely in both cases.
• Running each load left coffee grounds on the fabric.
• Using the standard amount of water in the colors cycle, the stain strips are about 4% cleaner than the strips we ran in the cycle with extra water.

So, does manually adding water to your washing machine help?

Nope! Using additional water does not get your laundry any cleaner. The extra water dilutes the concentration of detergent. Plus it reduces the mechanical action of the clothes rubbing against one another, the tub, or the agitator, which helps remove dirt and stains.

If your clothes aren’t getting clean enough, try this

You shouldn’t add more water to achieve cleaner clothings. There are other strategies you can implement, instead.

• Don’t overload your washer with clothes. Your laundry needs space to move around.
• Try using the heavy cycle on your washing machine.
• Use a better laundry detergent. When we tested liquid laundry detergents, Persil ProClean worked best, removing 2% more stains than Tide HE Turbo Clean, which is our best value detergent.
• Use less detergent, not more. Too much detergent can make your clothes feel soapy and greasy, and it can leave behind white spots. Filling the cup more than a third full is a mistake. A couple of tablespoons of liquid laundry detergent will work in many cases.
• Shake loose dirt out of clothes before you put them in the washer.
• Pretreat stains with cold water or stain remover before you wash.