Will a Dishwasher Work With No Hot Water (Let’s Find Out)

Having a dishwasher within your home is, without a doubt, a luxurious thing. Whether your water heater is not working or you’re trying to save money on your energy bill, you might be looking into cleaning your dirty dishes with cold water instead of hot water. That leads to whether a dishwasher can work with cold water or does it have to be hot. Let’s find out.

You can run a dishwasher without hot water, but you won’t get the same result in terms of cleanliness for your dirty dishes. Using cold water would not ruin your dishwasher either. 

However, having a hot water supply helps sanitize and get your dishes cleaner, as a hotter temperature equals killing germs and bacteria better. Some modern dishwashers will offer a heat boost option to heat water, but most models do not.

Dishwasher manufacturer installation calls for a supply line connected to the hot water supply. However, in some rare instances, I have seen dishwashers connected to the cold water supply. Most of these had an under sink hot water heater (point of service) installed.

Given the information above, let us understand more about the temperature used for a dishwasher and if there may be any issues occurring from using cold water. Keep reading to find out more! 

Can You Use a Dishwasher With No Hot Water?

Yes, you can use a dishwasher with no hot water, as briefly mentioned above. Cold water does not harm the dishes in any way, but it won’t have clean dishes and silverware when the wash cycle completes.

What we mean by this is that warm water is highly effective at sanitizing and killing off microorganisms and bacteria, according to the USDA (US Department of Agriculture). In that case, it is best to run the dishwasher settings hot. 

On top of that, many dishwashers come with a heating element at the bottom, so it is relatively hard to keep the internal thermostat at your desired temperature in the first place.

Do Dishwashers Need Hot Water Supply?

To save money, some homeowners may wish to decrease hot water consumption while running the dishwasher. Although it sounds like an excellent idea, your dishwater won’t clean as well in washing cycles. The internal thermostat inside some models boosts water temperature but isn’t designed to fully heat cold water. Hot water helps break down food particles and keeps residue from occurring.

Given that information, a dishwasher needs to run on hot water. It will clean much better with the hottest water possible, so we recommend those settings if that is an option.

In other cases, there may be a dishwasher model with a bad heating element. If this is the case, then the quality of how clean your dishes become will not be the best the longer you keep that model.

For example, if you have a modern dishwasher, they might have electric heating elements that warm the unit’s interior. However, if you acquired an average dishwasher, you might need to put hot water in yourself manually. 

The heating element in the bottom of the dishwasher is for drying dishes, not the heating process of cold tap water.

What is the Ideal Dishwasher Water Temperature?

According to GE products, the ideal dishwasher temperature is between 120 to 150 degrees Fahrenheit. If installing the dishwasher yourself, please connect the dishwasher to the hot water line instead of the cold. 

In commercial kitchens, when washing dishes the water needs to be 165 degrees Fahrenheit to sanitize dishes. Most incoming hot water in residential homes is between 105 and 115 degrees. The heat boost option raises the water temperature for washing dishes, but it won’t be effective on straight cold water.

If you suspect your water temperature is not hot enough, use a meat thermostat to check and see how hot it is. You do this by taking the following steps:

  • Turn the faucet on nearest to where the dishwasher is.
  • Get a cup or glass, then put the thermostat inside.
  • Afterward, allow the water to run inside the cup for a couple of minutes.

If the water heater is relatively far away or you have a mechanical or knob controlled-dishwashers, make sure to run the water in the sink so it can get hot before running the machine itself. 

Do Dishwashers Need a Direct Hot Water Input?

Washing machines have a cooling cycle for clothes, so you might be wondering if dishwashers do the same. A dishwasher directly connects to the hot water line and only needs hot water for cleaning. Dishwashers also do not have a cold or warm cycle. 

Will My Dishwasher Work if the Water Heater is Broken?

Suppose your water heater just broke and you need it fixed. In that case, it might be wise to rethink that strategy because a dishwasher will not work if the water heater breaks or turns off. 

Realistically, you can heat water up on the stove and place it in the dishwasher if you genuinely wish, but this would be more of a daunting task in itself. 

If this is the case, your best bet is to call a professional to fix the water heater and do your dishes by hand until it finishes. 

What are Some Signs a Dishwasher isn’t Using Hot Water?

If you suspect your dishwasher is not using hot water, then there are a few physical signs to look for. You could easily use a meat thermostat to help identify this issue, as we mentioned above. 

However, some people do not wish to take this approach, and you might see other noticeable things beforehand. 

1. You Have Dish Detergent Residue

Heat gets rid of soapy residue unless you have a specific brand that constantly has this issue. However, dish detergent is much heavier than regular soap, meaning it will cut through grease and food relatively quickly.

However, intense water pressure and hot water take that residue away. If the water is not hot enough, the soap residue will remain there. 

Something else to keep in mind is that unheated water will keep the dish soap chemicals on your dishware, making it get into your body by eating and drinking it.

2. Food Remains on the Dishes

The last way to check and see if your water is not running at the desired temperature is to catch food particles on the dishes. One prominent sign is to check your silverware. 

Suppose you took your favorite alfredo meal in your room to eat and watch your favorite show, but forget about the dish for two days. 

In that case, the silverware will have caked alfredo sauce left on it. However, after running the dishwasher cycle, you found out that it is not coming off, even after scrubbing it in the sink for two whole minutes.

If this is the case, your dishwasher most likely is not running at a high enough temperature.

Conclusion

A dishwasher can and will work with no hot water to quickly go over everything. On the other hand, is it a wise decision to do so? Not really, but it is still doable. Dishwashers are ineffective at heating water to optimal washing cycle needs with cold tap water. At best, you’d end up with lukewarm water.

Remember that a dishwasher’s temperature should be between 120 to 150 degrees Fahrenheit, so if it does not reach those temperatures, make sure to check your water heater or have a professional look at it. 

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.
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