Water from a dehumidifier is not distilled, and you should not drink it
The water a dehumidifier collects is condensation—moisture pulled from the air in your home. It looks clear, but it is not the same as distilled water. Distilled water has been boiled and recondensed in a controlled way to remove minerals and contaminants. Dehumidifier water has straightforward cooled on a cold coil and dripped into a tank. Whatever was floating in your indoor air—dust, mold spores, bacteria, pet dander, cleaning chemicals—can end up in that tank.
The water may also pick up particles from the dehumidifier itself as it sits in the collection bucket or reservoir. If the bucket is not cleaned regularly, bacteria and mold can grow in the standing water, making it even less safe. For these reasons, water from a dehumidifier should not be used for drinking, cooking, or filling humidifiers or aquariums.
Key Takeaways
- Dehumidifier water is condensation from indoor air, not distilled water, and contains whatever particles and contaminants were in that air.
- The collection bucket itself can harbor bacteria and mold if not cleaned regularly, adding biological contamination to the water.
- Safe uses for dehumidifier water include watering outdoor plants, cleaning floors, or filling a toilet tank—anything that does not involve ingestion or contact with food.
- If you want truly distilled water for appliances or drinking, purchase it from a store or use a home distillation unit designed for that purpose.
What is actually in dehumidifier water
Indoor air contains more than just moisture. It holds dust, pollen, pet hair, skin cells, cooking vapors, and whatever chemicals are in cleaning products or air fresheners you use. When a dehumidifier cools air on its evaporator coil, the water condenses out, but the other particles do not disappear—many of them end up in the collection tank along with the water.
The exact contents depend on your home. A house with pets will have more dander. A home where someone smokes will have nicotine and tar compounds in the condensate. A kitchen will collect cooking oils and salt spray. A basement may have mold spores if there is any mold growth. None of these things are removed by the dehumidifier process.
Over time, if the collection bucket sits for days without being emptied, bacteria and algae can grow in the standing water. This is especially true in warm weather or in a humid room where the bucket itself stays damp. A bucket that has been colonized by microbes is no longer safe for any use except watering outdoor plants far from food crops.
How dehumidifier water differs from distilled water
Distilled water is made by boiling water and capturing the steam, which is then cooled back into liquid. Because only the water molecules turn to steam—minerals and most contaminants do not—the result is very pure. Distilled water has almost no minerals, no bacteria, and no dissolved solids. It is used in car batteries, steam irons, and laboratory work because of this purity.
Dehumidifier water goes through no such process. It is straightforward air cooled on a metal coil. The water is pure in the sense that it is H₂O, but it carries whatever else was in the air. It is closer to rainwater collected in a bucket than to distilled water, except that indoor air is often dirtier than outdoor air.
If you need distilled water for a humidifier, CPAP machine, or car battery, buy it bottled or make it with a home distiller. Do not use dehumidifier condensate as a substitute.
Safe ways to use dehumidifier water
Dehumidifier water is useful for tasks where purity does not matter and where the water will not be ingested or absorbed through skin. Watering outdoor plants is the most common use—the minerals and particles in the water are actually beneficial to soil. You can also use it to water houseplants, though some people prefer distilled water for sensitive plants like orchids or carnivorous plants.
Cleaning floors, windows, and outdoor surfaces is another safe use. The water works just as well as tap water for mopping or rinsing, and you are not wasting treated municipal water. Some people use dehumidifier water to fill toilet tanks or to top off a car radiator in an emergency, though neither is ideal long-term.
Do not use dehumidifier water in humidifiers, steam irons, or CPAP machines. The minerals and particles will clog or damage these devices. Do not use it in aquariums or for watering edible plants that you will eat raw. Do not give it to pets to drink.
How to keep dehumidifier water as clean as possible
If you plan to use dehumidifier water for anything, keep the collection bucket clean. Empty it at least once a week, or more often if the dehumidifier is running constantly. Rinse the bucket with clean water and dry it before replacing it. If you see slime, discoloration, or smell anything off, scrub the bucket with a brush and a little bleach, then rinse thoroughly.
Some dehumidifiers have a continuous drain option where you connect a hose to the unit and run it to a floor drain or outside. This prevents water from sitting in a bucket and is the best way to avoid bacterial growth. If your dehumidifier has this option, use it.
Even with a clean bucket, remember that the water still contains whatever was in your indoor air. It is not sterile and should not be used for anything that involves drinking, cooking, or close contact with food.
When to call a professional about dehumidifier water quality
If dehumidifier water smells foul, looks discolored, or has visible growth in the bucket, the unit or the bucket itself may have a mold or bacterial problem. This is usually solved by cleaning the bucket and the coils inside the dehumidifier, which you can do yourself with a soft brush and mild soap.
If the problem returns quickly after cleaning, the dehumidifier may have mold growing inside the unit itself. This is more common in units that are not drained regularly or that sit in very humid conditions. A technician can open the unit and clean the internal coils, or you may need to replace the dehumidifier if it is old or heavily colonized.
If you are concerned about the air quality in your home and want to know what is actually in your dehumidifier water, you can send a sample to a water testing lab. This is not necessary for most homes, but it can be useful if you have health concerns or suspect mold or chemical contamination in your indoor air.
Frequently Asked Questions
Can I drink dehumidifier water if I boil it first?
Boiling will kill bacteria and some viruses, but it will not remove minerals, dust, or chemical particles. The water will still contain whatever was in your indoor air. For safe drinking water, use tap water (which is tested and treated) or purchase distilled water.
Is dehumidifier water the same as rainwater?
They are similar in that both are condensed moisture from the air. Rainwater is generally cleaner because outdoor air is less polluted than indoor air in most homes. Neither should be used for drinking without treatment, but both are fine for watering plants or cleaning.
Can I use dehumidifier water in my humidifier?
No. Humidifiers need distilled or demineralized water to prevent mineral buildup and mold growth inside the unit. Dehumidifier water contains particles and minerals that will clog the humidifier and reduce its lifespan.
What if my dehumidifier water looks completely clear?
Clear appearance does not mean the water is pure. Bacteria, viruses, and dissolved chemicals are invisible. The water can look perfectly clear and still contain contaminants from your indoor air. Clarity is not a sign of safety.
Is it wasteful to throw away dehumidifier water?
No, because you should not be throwing it away—use it for outdoor plants, cleaning, or other non-consumption purposes. If the bucket has visible mold or smells bad, then yes, discard it. Otherwise, find a use for it rather than letting it go down the drain.