Is Dehumidifier Water Good for Plants?

Stephen Andrews
10 Oct 2023

You may wonder if it’s a good idea to give your cannabis plants the water that collects in dehumidifiers. Dehumidifiers trap vapor and moisture in the room where they stand, therefore this is a type of deionized graywater. If the air inside the room is clean, it’s relatively safe to repurpose this water for some of your gardening activities.

Using dehumidifier water is in a way similar to rainwater. This type of water can be used for both indoor and outdoor plants, given that the air inside your home is clean and there aren’t any impurities that can deposit in the collected water. 

Dehumidifiers can trap vapor and moisture from air. If the air in the room is clean, then the water will also be clean. But if there’s mold on your walls or if you have plants where you see visible signs of fungal damage, watering your plants with dehumidifier water may be something you want to skip. 

The presence of mold or fungi in the room indicates that there could be fungal spores floating in the air, which can also concentrate in the dehumidifier. And when the collected water is contaminated with these particles, that’s definitely not good to use on any plants that you plan to consume. 

What Can End Up in Dehumidifier Water? 

Dehumidifiers virtually absorb all moisture that’s in the air, the carpets, the walls, on the windows, and pretty much everything in your home that can soak up moisture. The absorbed water can contain various volatile organic compounds (VOCs), or substances that easily become vapors or gases. We inhale such gases from many commonly used products, such as gasoline, fuels, paints, air fresheners, cleaners, personal care products, and even new furniture.

Dehumidifier water can also become a host of other impurities or microorganisms. The devices are usually made of plastic materials, which are not optimal to preserve water. The material can affect the quality and smell of water, in other words the chemical content of the fluid. It also matter whether the dehumidifier is clean or not. When not properly maintained, it can attract other microbes that thrive in dirty environments. Studies have also shown that dehumidifier water can also contain compounds with potential allergens. 

Can You Purify Dehumidifier Water?

The water quality from a dehumidifier is primarily determined by the quality of air in your home. If you use an air purifier, it will probably be much safer to use dehumidifier water for any plants that you want to grow, including cannabis. Another thing that can help is using an active charcoal filter to remove some impurities in the dehumidifier water

If you are still skeptical of using dehumidifier water for your cannabis plants, you can perform a water analysis test and determine whether it's appropriate for use or not. Anyhow, there are plenty of other ways to repurpose dehumidifier water around your household. You can use this water for washing clothes, cleaning windows, mopping the floor, etc. 

What not to do with dehumidifier water? Just don’t drink it. 

Also read on Soft Secrets:

- Can You Use Baking Soda in Your Garden?

A Beginner’s Guide to Top Dressing and Organic Tea

- Can You Heal a Dying Cannabis Plant? 

Stephen Andrews