Does A Dehumidifier Need Water?

If you’ve seen a dehumidifier up close you may have noticed that portable models typically include a water tank somewhere located at the base of the unit.

Depending on how long a dehumidifier has been operating, the water tank can be anywhere from empty to full.

Does this mean that a dehumidifier needs water to operate?

A dehumidifier does not need water to work. A dehumidifier extracts moisture from the air inside a building and collects it as water inside a tank. Dehumidifiers shouldn’t be confused with humidifiers, which need water in order to increase humidity of the air.

For example, we use our dehumidifier to help reduce the moisture level of the air in our home.

This helps things like laundry to dry faster and helps to prevent condensation and buildup of mold.

Dehumidifier Drying Washing
Our dehumidifier removing moisture from the air in the room allowing our clothes to dry out faster

Read on to learn more about dehumidifiers and water.

Does A Dehumidifier Need Water To Operate?

Putting water in your dehumidifier is unnecessary. Since it’s pulling water out of the air, placing water inside serves no purpose. Doing so will simply be putting more strain on the appliance and prevent it from operating at its full potential.

The liquid appears in a dehumidifier after a simple process.

This collection process of water inside a dehumidifier includes:

  • Drawing humid air into the machine
  • Collecting condensation inside small coils or absorbing moisture, depending on the type of dehumidifier being used
  • Releasing drier air into the room

The water that gathers is a result of this process and not for any other reason. No step in this process requires water in order for a dehumidifier to work.

As a result, there’s no need to add water to a dehumidifier.

If there’s water in a dehumidifier then it’s the moisture from the air that it’s already collected.

Dehumidifier Water Level
This tank is half full

What Happens if You Put Water In A Dehumidifier?

Putting water in the tank of a dehumidifier won’t damage it.

However, you’ll fill up the space for water collection unnecessarily.

This action can lead to the tank being full and the dehumidifier turning off prematurely.

Adding extra water might also encourage the growth of bacteria and mold if left for longer periods of time

Dehumidifier Drain Channel
Adding water to a dehumidifier could promote mold growth

It’s best to avoid adding water and leave the dehumidifier to operate for itself. All you need to do is leave the dehumidifier to its job and empty it of the water when the tank is full.

Dehumidifier Emptying Water
Emptying the water tank on our dehumidifier

How Much Water Can A Dehumidifier Hold?

Not all dehumidifiers are created equal, so it’s important to know how much water your appliance can hold once it’s in operation.

There are a few different capacities that dehumidifiers can handle. The most common include:

  • 10 pints
  • 50 pints
  • 100 pints

All of these are common capacities.

Knowing how much your dehumidifier can hold will allow you to determine how long it can run before you need to empty it.

As an example, our dehumidifier can hold over 10 pints (6.5 liters) and can run for around 16 hours before the tank typically becomes full.

Dehumidifier Water Tank

You shouldn’t leave water in the tank for longer than it needs to be there, as a dehumidifier doesn’t need water to run.

Does Water Need To Be Drained From A Dehumidifier?

Water doesn’t need to be drained from a dehumidifier unless the tank is full. However, on certain portable units it can be possible to set up continuous drainage where the dehumidifier doesn’t need to be manually drained.

There are three main ways water can be drained from a dehumidifier, which include:

  • Manually draining
  • Using gravity
  • Utilizing an external pump

Manually Removing The Bucket

One option is to manually remove the water tank.

This step might look different on varying dehumidifiers, but generally, there are a few steps you can follow to remove the water tank and pour away the water (or use it for something else).

To remove the bucket, you should:

  • Open the container at marked locations
  • Pull the bucket out
  • Drain it
  • Replace the bucket

This process will allow you to remove water from the device with your hands rather than relying on another mechanism.

A dehumidifier can’t continue to operate unless the water is emptied when the tank is full.

A dehumidifier should automatically turn off when it fills up (and possibly make beeping noises like ours does), so you shouldn’t have trouble understanding when it needs to be emptied.

Emptying a tank manually as quickly as possible will allow your dehumidifier to get straight back to moisture removal.

Use Continuous Gravity Draining

You might also use gravity draining to empty a dehumidifier.

There’s often a tiny slot on the appliance where you can attach a tube to the tank.

By following a few steps, you can remove the water from the dehumidifier by utilizing gravity. This method is preferred by many over the other two.

Dehumidifier Water Tank
There’s a slot on our dehumidifier that can be removed to set up continuous drainage

This method can be the easiest. It requires little effort, especially if you position the dehumidifier close to a sink or another drainable location.

Tubes are cheap, and many come with the dehumidifier when buying new.

Utilize External Pumps

The final method that you might make use of is an external pump.

These are machines that hook up to your dehumidifier and are responsible for pushing water through a tube and to the location that you want it to drain.

With external pumps, you can buy a dehumidifier with one built-in or invest in a separate water pump.

This option is more expensive, but it can make life much easier for you as it is much less hands-on. The money can be well worth it for some to avoid extra work.


A dehumidifier does not need water to operate.

Dehumidifiers instead collect moisture from the air and store it as water in a tank.

Adding water can limit the capacity of the dehumidifier, leading to the need to empty the dehumidifier earlier and more often.

Further Reading

Why A Dehumidifier Isn’t Collecting Water

How Much Water A Dehumidifier Should Collect In A Day

Do Dehumidifiers Need To Be Emptied?