Can You Water Plants With Dehumidifier Water? (What You Need to Know)

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Can You Water Plants With Dehumidifier Water?

With growing concerns about dwindling groundwater levels, people have never been more aware of water wastage. Depending on the humidity and the size of your dehumidifier, some units can extract a substantial amount of water each day. You might be wondering if you can put this water to good use in your garden.

You may water your plants with dehumidifier water, which is a cleaner version of your typical home greywater. However, you should avoid using this water on your edible plants as it may contain heavy metals and microbial pathogens. You should also bear in mind that this water is nutrient-poor. 

Just because your dehumidifier condenses water from the air does not make the water pure or safe for consumption. However, you may use the water on your plants and flowers safely, provided you don’t intend to eat them. Here are some reasons why you should take care with your dehumidifier water.

Using Dehumidifier Water for Plants: What You Need to Know

As I mentioned above, dehumidifier water is a cleaner version of graywater, and you may use it to water your plants. However, the University of Massachusetts Environmental health and Safety department warns that dehumidifier reservoirs may harbor mold and bacteria that pose a health risk.

Although your dehumidifier water may pass the TDS meter readings, it does not mean that the water does not contain toxins. A TDS meter or Total Dissolved Solids meter is a small handheld device used to show the amount of dissolved solids in a solution.

Low metal levels such as zinc (under 5.0ppm) and copper (1.0ppm) may not show up on the TDS but still pose a risk for your edible plants. Bioaccumulation of toxic metals may pose a risk for human consumption.

Likewise, dehumidifier water may be a breeding ground for pathogens, especially if you don’t clean and disinfect your dehumidifier regularly. By using raw dehumidifier condensate, you run the risk of contaminating your plants with these pathogens.

That being said, dehumidifier water is one of the cleaner versions of greywater, and provided your plants are not meant for consumption, you may reuse the water for your indoor and outdoor plants. However, it would be best to consider the following facts before using your dehumidifier water for your plants.

Dehumidifier Water is Nutrient Poor

Rain is enriched with atmospheric nutrients such as nitrogen and is naturally infused with minerals from rocks and soil. These nutrients essential for healthy plant growth are not found in dehumidifier runoff.

Water accumulated in dehumidifiers is partially demineralized, so long-term use for watering your plants may result in mineral deficiencies. You may want to consider using supplemental fertilizer if you intend to use only dehumidifier water on your plants.

Although information regarding the pH of dehumidifier water is contradictory at best, you may need to consider testing your dehumidifier water for pH levels. Some plant enthusiasts report pHs as low as 5.0pH due to the increased absorption of C02 of the demineralized dehumidifier water.

Dehumidifiers and Trace Metal Bioaccumulation

Dehumidifier reservoir water is a cleaner version of typical greywater, suitable for human consumption, but one may use the water waste for gardening purposes. Wastewater from your dehumidifier may contain trace elements of metals contained in the galvanized steel support and drain pan such as:

  • Copper
  • Aluminum
  • Zinc
  • Lead

These metals have a tendency to bioaccumulate, which means that these metals might stay in the water, or plants may absorb these metals and, in return, enter our bodies by eating the contaminated plants.

Because of the chemical composition of these heavy metals, they are not processed/released by the living organism that consumes them. This bioaccumulation means that these toxins increase concentration as they move up the food chain.

Dehumidifier Water May Contain Pathogens

Volatile organic compounds in the air may dissolve in the dehumidifier condensate and provide a fertile breeding ground for microbial growth. Both the plumbing and water storage areas may be sites of water contamination typically measured by heterotrophic plate counts (HPC.)

HPC is a procedure for calculating the presence of live heterotrophic bacteria in water. The test provides valuable information about water quality and the safety of tested water sources for human consumption.

Although the presence of microorganisms does not necessarily correlate to direct human health risks, high HPC results suggest water conditions favorable for potentially harmful microbial growth. Opportunistic pathogens that thrive in drinking water include  Legionella spp. and Mycobacterium spp.

Dehumidifier water is a condensate, not a distillation. Thus, the dehumidification process does not include the sterilization protocols necessary to decontaminate the stored water from potential microbial pathogens.

Dehumidifier Water is Not Pure

A typical public misconception exists between the concept of condensation vs. distillation. Condensed dehumidifier water is a liquid created by drawing air across the colder coils. This process causes the water to condense on the dehumidifier surface, changing the phase of the airborne water to liquid.

Desiccant dehumidifiers or absorption dehumidifiers collect condensate by bonding moisture with water-attracting materials such as silica gel. Distillation is a process that involves separating the components of a liquid mixture by using heat and is a technique of separation. In contrast, condensation is merely a process of changing the phase of matter.

The reservoir water collected by both dehumidification systems may pass through a filter but remains impure. The water in the dehumidifier system comes into contact with plastic and metals and absorbs airborne contaminants, dirt, and dust.

The dehumidification system was not engineered as a water purification system and thus does not conform to EPA guidelines regarding water for human consumption coming into contact with contaminating materials such as metal and plastic.

These potentially harmful microorganisms may be absorbed in your edible plants and pose a health risk. However, non-edible and ornamental plants will not pose the same dangers of ingestion, and one may use the water for this purpose.

Dehumidifier FAQs

Can I Use Dehumidifier Water on my Flowers?

Dehumidifier water is fine to use on your flowering shrubs as long as they are not of the edible variety. Dehumidifier water is a cleaner version of your household greywater, and you may recycle it safely in your indoor and outdoor plants.

Can I Use Dehumidifier Water on my Carnivorous Plants?

You should not use dehumidifier water on carnivorous plants such as the Venus Fly Trap as these plants require properly distilled water, osmosis water, or rainwater. Carnivorous plants such as the Venus Fly Trap are particularly sensitive to waterborne minerals and waterborne dissolved solids.

Can I Use Dehumidifier Water on My Tomato Plant?

You should never use dehumidifier water on any plants you intend to use for human consumption. The water may contain pathogens and microbial contaminants that collect in the reservoir and traces of heavy metals. These metals may accumulate in your plant, and you may ingest them. 


You need not waste your dehumidifier water when you can put it to good use in your garden and home. Remember that the water from your dehumidifier reservoir is condensate, not purified distillate, and treat it accordingly.


You may also be interested in… Can You Drink Water From a Dehumidifier?Can You Use an Extension Cord With a Dehumidifier? and Are Dehumidifiers Bad for Pets?