Watering Plants with Dehumidifier Water: A Complete Guide

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People start looking for ways to use less water in the summer when many places are in drought or can’t water their plants. Some dehumidifiers have a reservoir that holds water. If you have one, you may have noticed this.

The water from the dehumidifier might not go down the drain after all. Instead, you could use it to water plants on your windowsill, deck, or patio without having to use the garden hose or watering can. However, should you really use dehumidifier water for plants?.

We spoke to experts to get the scoop on using dehumidifier water for plants at home. Heres what they had to say.

Using the water collected in your dehumidifier’s reservoir to hydrate your plants seems like an eco-friendly, money-saving idea. But is it actually safe for your plants? In this comprehensive guide, we’ll examine the pros and cons of using dehumidifier water on houseplants and outdoor gardens.

What is Dehumidifier Water?

A dehumidifier removes moisture from the air in your home and collects it in a tank or bucket. This happens through a refrigeration process that condenses water vapor out of the air.

The water collected is essentially distilled water – pure H2O. However, as it condenses, the water can pick up:

  • Dust and dirt particles
  • Mold, bacteria, and microorganisms
  • Trace amounts of metals from the dehumidifier’s coils

So while relatively clean dehumidifier water isn’t filtered or disinfected. It’s considered “graywater.”

Is It Safe for Plants?


Dehumidifier water is generally safe for watering most indoor houseplants. The small amounts of potential contaminants are unlikely to harm them

The exception would be plants you plan to eat – like herbs, lettuce, or tomatoes. For edibles, it’s better to use filtered or distilled water to limit any bacteria or mold exposure.

Outdoor Plants, Gardens, and Lawns

Dehumidifier water can also be used to water outdoor plants, gardens, trees, and lawns. The dilution from outdoor watering minimizes any potential risks.

During droughts or watering restrictions, it can provide a free alternative to keep your outdoor plants hydrated. Just be sure to:

  • Water early in the morning to allow time for drying
  • Direct water at the roots and soil, rather than spraying leaves
  • Rotate watering locations to prevent pooling
  • Don’t use dehumidifier water on edible gardens

Outdoor plants are very forgiving when it comes to using graywater sources. Just avoid pouring directly on plant leaves to limit mold growth.

Benefits of Using Dehumidifier Water

  • Saves money – Reduce your use of tap water and water bills

  • Conserves resources – Every little bit of water savings helps in drought-prone areas

  • Lowers humidity – Removing water from the dehumidifier tank helps it work more efficiently

  • Adds nutrients – Trace amounts of nitrogen, phosphate, and potassium

  • Pure H20 – Devoid of chlorine, fluoride, and other tap water additives

Drawbacks of Dehumidifier Water

  • Mold risk – Stagnant tank water can harbor mold and microbes

  • Metal traces – Possible leaching of copper, zinc, and lead from coils

  • Sodium content – Higher sodium concentration than tap water

  • pH level – Slightly acidic pH around 5.0-6.0

  • Not sterilized – Contaminants aren’t filtered out before watering

  • Limited supply – Dependent on dehumidifier tank capacity

  • Plant reactions – Some salt-sensitive plants may object (orchids, African violets)

Tips for Using on Plants Safely

  • Clean tank and change water frequently to limit mold
  • Don’t use on plants you plan to eat raw
  • Alternate dehumidifier water with normal waterings
  • Stop if plants show signs of stress like yellowing leaves
  • Test pH and dilute with tap water if too acidic for your plants
  • Rinse edible plant leaves after watering to remove residues

Final Verdict: Give it a Try!

While not completely sterile, dehumidifier water is generally safe for watering your non-edible houseplants and outdoor gardens.

The small risk of mold, bacteria, and heavy metals is outweighed by the benefits of conservation and reducing tap water usage.

Be smart about usage – avoid standing water, change tank water frequently, rinse edibles after use. And monitor your plants for any signs of stress. But otherwise, this free, eco-friendly water source is perfect for keeping your plants lush and hydrated!

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Most people don’t even clean their dehumidifier reservoirs, let alone look into them. They also don’t empty the reservoir unless they have to, which means that mold and other microorganisms can grow in it for a long time.

Because it could be contaminated, dehumidifier water is a type of gray water. Gray water has been “used” for something, like washing dishes or taking a shower, but it doesn’t contain sewage. Some worry that heavy metals from the cooling coil might get absorbed into the dehumidifier water. Others say that the amount of copper, zinc, and aluminum in a dehumidifier’s water reservoir is minimal.

That said, dehumidifier water isn’t filtered or treated after it comes off of the dehumidifier coils. If there is heavy metal contamination, it’s not coming out—and you won’t know if it’s there unless you pay for a laboratory test. Still, contamination by mold and microorganisms is much more likely.

What’s in dehumidifier water?

watering plants with dehumidifier water

Dehumidifiers take the moisture from the air by cooling it down, making your room less stuffy or moldy.

A dehumidifier cools the air in your room, which makes water droplets form in the air and collect in the dehumidifier’s water tank. The dehumidifier then passes the air over warm coils before blowing it back into the room.

This process (cooling moist air until water condenses out) is how we get rain. It’s not distillation, which involves boiling water, and makes water safe to drink. Any germs, mold, or dust that were in the air or on the fan will be in the water when it gets to the humidifier reservoir because it hasn’t been boiled.

Is Dehumidifier Water Safe for Plants?

Is dehumidifier water good for plants?

According to Water Management Specialist Janet Manning, dehumidifier water – which is a form of gray water (used water in your house that normally goes down the drain) – can be good for indoor and outdoor plants if the air inside your home is clean, as it’s a bit like using rainwater.

Can a dehumidifier irrigate indoor plants?

And since about 30% of drinkable water in the U.S. is used to irrigate outdoor plants, during a drought it’s a good idea to use any gray water you can for watering your yard. When it comes to indoor plants, you can use water from a dehumidifier to give your thirsty houseplants a drink.

Can you use a dehumidifier in a drought?

Water from a dehumidifier is good for watering plants outside your home during a drought. And since about 30% of drinkable water in the U.S. is used to irrigate outdoor plants, during a drought it’s a good idea to use any gray water you can for watering your yard.

What can you use dehumidifier water for?

Ultimately, you can spend a significant amount of time finding the most valuable ways to use your dehumidifier water. Still, the most common and rational use for it would be using it to water your plants. Almost all plants can use the water generated from dehumidifiers with little to no side effects.

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