Do You Put Water In A Dehumidifier? [You’ll Be Surprised!]

Humidity is a measure that shows how much water vapor the air has. Since a dehumidifier is an appliance to regulate humidity, it is no wonder that many people will ask if they need to add water to it. 

Simply put, a dehumidifier doesn’t need water to operate. On the contrary, it will turn moisture in the air into water by itself.

I will illustrate more details about this topic in the following sections. Please continue to read if you want to know the reason behind it, and in which case, you can put water in a dehumidifier.

Does a dehumidifier need water to work?

To answer this question, we must first figure out how a dehumidifier works.

There are two types of dehumidifiers: refrigerant and desiccant dehumidifiers. Most household dehumidifiers are refrigerant units.

These units will draw the air into the machine by means of a fan. The air will pass through an evaporator coil which has a low temperature.

When the air reaches its dew point, the water vapor will convert to liquid, accumulating in the water bucket. Next, the cool and dry air will be reheated before returning to the room.

Desiccant dehumidifiers work on different principles. When the air gets into the device, it will go through a wheel that can absorb moisture by making use of silica gel. Then the moisture in the wheel will be taken away by warm air and then condensed out as liquid water.

No matter which type of dehumidifier you choose, a dehumidifier needs air to operate rather than water. It can produce water, so you don’t need to put water in it.

Consequences of putting water in a dehumidifier

Since every room dehumidifier has a water tank, adding water to it will not damage your dehumidifier.

For example, when the water supply will be cut off in your house, you can use the dehumidifier water tank to catch some water.

However, it is not advisable to do it in normal operation. There is a sensor in the water tank to detect the water level. If you put water into it beforehand, the dehumidifier will fill up faster.

Once the tank is full, the dehumidifier will shut off automatically, making your machine not able to remove adequate excess moisture in the air.

If the water sensor malfunctions, keeping water in the tank can make the machine more prone to leakage.

In addition, leaving water in the dehumidifier may promote mold growth. When the water sits in the tank for enough time, it will become a thriving environment for those contaminants to proliferate. Mold spores can get into the air, posing health risks to us. Things can get even worse if you put tap water into it.

Therefore, unless using the water tank as a bucket to store water, you shouldn’t add water to your dehumidifier.

How much water can you put in a dehumidifier?

do you add water to a dehumidifier

If you still insist on adding water to your dehumidifier, you should check how much water you can put in. 

Different from how much water your dehumidifier can collect per day, this is decided by the size of the water tank. Sometimes, a dehumidifier that can collect 70 pints per day has a water tank that can only hold 10 pints of water.

Many people assume dehumidifier capacity is the amount of water their machines can hold, which is not true. You may find a more suitable container to store water.

In case you want to run the dehumidifier but still keep the bucket full, you can drain the dehumidifier in other ways. Connecting the dehumidifier to a hose with or without the help of a pump can make sure the collected water is sent to the floor drain.

How do you deal with the collected water if you decide not to put water in a dehumidifier?

Until now, you have understood why you don’t need to add water to a dehumidifier. You may be curious about how to use the collected water. 

Despite dehumidifier water is not as pure as distilled water, you can use it to water plants, wash your car, or even add to your humidifier

Note that it is not drinkable even if it appears to be as clean as tap water.


Dehumidifiers are different from humidifiers. They don’t need water to work, and you don’t need to add water to them. 

Because a dehumidifier can make water itself, adding water will cause the machine to fill up quickly and can’t control the humidity level as usual. The stagnant water can also become the breeding ground for mold and bacteria. 

While you can use the bucket as a container to store water, you will not reap any other benefits from putting water in it. 

About The Author

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested dozens of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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