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How Hot Do Dishwashers Get?

A collage of dishwasher and its part.

You may have wondered what goes on inside your dishwasher when you hear water spraying, gurgling, and draining. It might sound more like a washing machine than a puddle of water being sprayed onto your dirty dishes. You’d be right.

Dishwashers use 130 to 140-degree water with which to clean your dishes. Most water heaters, from whence the water comes, only heat water to 120 degrees. How can that be? How do dishwashers operate at such high temperatures? Read on to find out.

How Does The Water In Dishwashers Reach Such High Temperatures? Do They Have Their Own Water Heater?

In a manner of speaking, yes, they do. If you open your dishwasher and look into the tub, you’ll see elements lining three sides of the tub. These are the heating elements. As water enters the tub, it enters at the temperature of the water heater or 120 degrees.

The heating element kicks in to raise the temperature of the water to 130 or 140 degrees. This is necessary for two reasons:

    • Very hot water rehydrates dried-on food particles stuck on the dishes. It then dissolves the soap to wash the particles off and clean the dishes.

    • Note that in the final rinse, the water is super-heated to up to 180 degrees. This is necessary for the sanitation of the dishes. You’ll want every particle of bacteria destroyed for the peak good health of you and your family.

How Does The Very Hot Water Interact With The Dishwasher Soap?

Inside look of a dishwasher.

Now the water and detergent combine to be sprayed through the spray arms to clean the dishes. After the soapy water drains after the first rinse, clean water enters the tub. The heating elements re-heat the water, it’s sprayed on the dishes in the main cleaning cycle, and the water drains once more.

The third cycle, or the final rinse, is when the very hot water sanitizes the dishes. The grime has been washed off them, and they’re ready for the final show. Now, when the water drains, the dishes are steamed in order to dry them. Voila, your dishes are clean.

What Could Impede The Very Hot Water From Cleaning Every Dish In The Dishwasher? There Are Times Mine Don’t All Get Clean

A dirty dishes on dishwasher.

There are two spray arms, one on the bottom of the tub and one on top. Sometimes grime sprays up from the bottom and gets on large pans or bowls turned upside down on the bottom rack.

There are occasions when large platters block the spray arm on the bottom, leaving the cups and bowls on the top rack still besmirched. The placement of dishes in a dishwasher is vital to the cleaning and sanitation of every dish.

Whatever could block the spray arms, bottom or top should be removed from the dishwasher and washed by hand in the kitchen sink. We all have our favorite method of stacking a dishwasher, but be aware of those spray arms when you do.

Can A Dishwasher’s Water Not Be Hot Enough? How Would I Know If This Was The Case?

There are two ways to tell. The first is that the dishwasher powder is clumped up in the cup and not dissolved at all. The second is that your dishes are still dirty. Call a professional to check (a) the water heater, and (b) the heating element in your dishwasher.

Can The Water Be Too Hot? One Hundred-Eighty Degrees In The Rinse Cycles Sounds A Bit Warmish

Woman setting dishwasher temperature.

Begin with your water heater. If it’s set to a temperature above 122 degrees, then ask a professional to adjust the temperature. If the heating element is set too high, then the enzymes in your dishwasher detergent won’t be viable. They won’t be able to clean the dishes.

Another problem too high heat can cause is lime deposits on your dishwasher. This will cut the efficiency of your dishwasher severely, so you’ll need a professional to look at it.

Cloudy glasses are another result of too high heat. The heat opens up the molecules in the glass, affecting the way light impacts the glass. You’ll still feel a smooth drinking glass, but the cloudy thing won’t go away.

Should I Know Anything Else About Dishwashers?

I grew up washing dishes as part of my “chores.” When they sold the house, the buyers said,  “but you don’t have a dishwasher.” My mother replied, “ Yes, I do! She’s thirteen.” This was in the mid-70s, so dishwashers weren’t quite the norm just yet in Nashville, TN.

They are now. Today’s dishwashers offer homeowners water-saving and power-saving features that make them way more useful than paying an unappreciative child to do it. Did you know it’s more cost-efficient to run the dishwasher at night? Many cities offer cheaper rates at night. 

Some Tips For Using Your Dishwasher

Woman getting dishes from the dishwasher.

1. If your dishes are coming out dull, splash a spoonful of white vinegar in the tub.

2. Run hot water in the kitchen sink before starting the dishes. Hot water will already be available, and the heating element won’t work overtime to heat the water. That shows up on your power bill.

3. Place utensils head down in the utensil cups. The spray arm can get to them better if dishes aren’t blocking the utensil cups.

4. I didn’t know this, so I’m passing it on to you: don’t pre-rinse your dishes or “wash” them before putting them in the dishwasher. Just scrape them. The soap needs something to which to attach so it can clean the dishes.

5. You can also use the dishwasher to wash the baby’s toys, baseball caps, small things like ashtrays, makeup trays, pet dishes, soap and toothbrush holders, sponges, and plastic sandwich baggies.

6. Clean your dishwasher every couple of months. Soap scum and hard water deposits can build up and make the machine less efficient. Run the dishwasher through a cycle, except throw in some white vinegar. If you don’t have any, lemon juice will do the same job.

How Hot Do Dishwashers Get FAQ

How Hot Does A Dishwasher Get In The Dry Cycle?

The heating element does double duty here. It warms the inside of the dishwasher between 110 to 170 degrees. If your dishes aren’t dry at the end of the cycle, call a professional to check the heating element.

Does A Dishwasher Sanitize Or Sterilize Dishes?

Dishwashers reach 171 degrees, which is the temperature at which the NSF requires sanitizing dishes. Sterilization is a totally different matter and requires 180-degree temperatures. Both are well within a dishwasher’s temperature range.

Should The Door Be Left Open To Dry The Dishes?

An open dishwasher with dishes.

It’s a good idea to open the door for a while so mold and mildew don’t grow in the warm, damp inside.

Is It Cheaper To Hand Wash Dishes Or Run The Dishwasher?

Studies show that dishwashers are more efficient using water and power than hand washing dishes, even if you wash all the dishes, pile them up, and then rinse them before drying.

Can You Leave Dirty Dishes In The Dishwasher Overnight?

You can, but you need to wash them the next day. Bacteria live on dirty dishes for up to four days and will spread around the kitchen if you don’t keep on top of it.

Are There Any Rules For Using A Dishwasher?

A hand holding the dishwasher rack.


    • Don’t wash deep pots or pans in the dishwashers

    • Don’t overload the machine

    • Don’t use too much detergent

    • Hand wash crystal and china

How Many Times Per Week Should The Dishwasher Be Run?

Experts say to run the machine once per week to prevent the seals from being ruined. If this doesn’t work for you, you can always run the dishes on a shorter cycle.