Portuguese 
Research published in 2026 shows that condensate from air conditioning units can be reused for irrigation, cleaning, and other non-potable uses, but analyses have found significant quality differences and even microbiological contamination.
The water that drips from air conditioning hoses and usually ends up on the ground or in the drain is garnering renewed scientific attention in 2026. Recent studies show that this liquid can represent a complementary source of water, especially when dozens or hundreds of units operate together.
However, this potential is accompanied by a caution. Despite its clear appearance, air conditioning water should not be automatically treated as pure or potable water.
Researchers have found significant differences in the composition of the samples, as well as microbiological contamination in certain cases. At the same time, surveys indicate that large installations may waste thousands of liters daily.
-
Scientists Create Self-Healing Metal That Fills Its Own Cracks When Heated
-
Brazilian City Makes History by Winning the World Smart City Award
-
Indian Prosthetic Leg Costs About $100, Can Be Made and Fitted in One Day, and Enables Squatting, Swimming, and Working Barefoot in Muddy Fields
-
Scientists Develop Hydrogen-Powered Car That Doesn’t Require Gasoline or Charging
The water is not produced by the unit
Air conditioners do not create water. The liquid appears because the unit removes some of the humidity present in the air during the cooling process.
When humid air comes into contact with the cold surface of the evaporator, some of the water vapor condenses. The droplets are directed into a pan and then drained through a drainage pipe.
Thus, the amount of water produced is not the same everywhere.
Air humidity, temperature, equipment capacity, operating time, and system characteristics directly influence the volume that can be recovered.
This explains why studies conducted in different regions found such distinct results and why there is no single number of liters that can be attributed to any residential unit.
2026 Study Found Contamination in Some Samples
A study published in 2026 in the journal Desalination and Water Treatment analyzed the condensate produced by units installed in administrative buildings in Saveh, Iran.
The study available on ScienceDirect concluded that the water exhibited favorable physicochemical characteristics, including low mineral content, low salinity, and low hardness.
However, the analysis revealed a detail that completely changes how this liquid should be regarded.
Researchers found microbiological contamination in some samples, including the presence of coliforms. According to the study, the results prevent the collected condensate from being simply classified as water suitable for human consumption without treatment.
In practice, seemingly clear water can carry microorganisms acquired during contact with the unit’s components, drainage system, storage container, or environment.
The results reinforce that appearance is not synonymous with potability.
Another Study Analyzed 30 Different Units
A second study from 2026 also illustrates why it’s risky to claim that all air conditioning water possesses exactly the same characteristics.
Researchers affiliated with the University of Medical Sciences of Iranshahr collected triplicate samples from 30 air conditioning units and assessed various chemical parameters.
The study published in the Journal of Advances in Environmental Health Research found an average pH of 7.13, total dissolved solids of 196.15 mg/L, and electrical conductivity of 296.74 µS/cm.
Total hardness averaged 305.62 mg/L as CaCO₃.
Sodium, calcium, magnesium, and chloride were also measured. The quality index calculated by the researchers varied from 32.14 to 126.6, a range classified in the study as moderate to poor quality.
However, the researchers did not dismiss the potential for reuse.
The conclusion highlighted a high potential for reuse, especially for non-potable purposes, such as irrigation, but emphasized that further studies are needed to evaluate safety, necessary treatment, and larger-scale usage.
The difference between the results obtained in Iranshahr and those found in other locations demonstrates that there is no universal composition for the condensate.
113 units produced nearly 6,000 liters per day
If the amount produced by just one air conditioner may seem small, the situation changes dramatically when the liquid from dozens of units is combined.
A comprehensive review published in April 2026 in the journal Discover Water analyzed 21 studies on recovering and utilizing water condensed by air conditioning systems.
The study published by Springer Nature collated experiences conducted in various countries and illustrated the extent to which this seemingly insignificant resource can reach.
In one of the evaluated cases, university buildings in Egypt equipped with 113 units produced approximately 5,977.7 liters of water per day.
That’s nearly 6,000 liters daily from something that would normally be simply discarded through drains.
Another study cited in the review found production between 10 and 30 liters per day in two-ton cooling units in Bahrain, with a strong correlation between the amount collected and the relative humidity of the air.
In China, a study revised by the authors calculated approximately 1.6 kg of condensate per hour and 52.99 kg per day per unit under peak conditions.
These figures do not mean that any residential unit will produce dozens of liters every day.
They are results obtained from different equipment, climates, capacities, and operating conditions. For this reason, the numbers should not be used as a promise of household production.
Collection systems can also offer financial returns
The 2026 review also analyzed whether installing a system specifically for recovering this water could make financial sense.
In a modeling study focused on institutions in Ghana, structures with approximately 10 units showed an estimated return on investment in 6.41 years.
With about 20 units, the calculated period decreased to approximately 3.21 years.
The proposed system collects water from the drains, guides the liquid through pipes, utilizes filtration, and directs the condensate to reservoirs.
Depending on the purpose, pumps, additional filters, sensors, and other components can be incorporated.
The concept gains traction mainly in universities, offices, hotels, hospitals, and other facilities where many units operate for several hours.
Irrigation, cleaning, and flushing appear among the possibilities
The studies indicate that the most direct application lies in uses that do not require potable water.
The 2026 review collates works that considered applications such as garden irrigation, floor washing, toilet flushing, and other non-potable household or institutional activities.
The study conducted with 30 units in Iranshahr also identified irrigation as a potential reuse option, although it highlighted the need to assess quality before usage.
This means that simply placing a bucket under the hose and using the water for any purpose does not necessarily reproduce the conditions studied by the researchers.
Collection, storage, equipment maintenance, and final disposal all impact safety.
Clear water does not mean safe drinking water
The key finding of the 2026 studies is precisely this contrast.
On one side, there is a resource that is typically treated as waste and, when gathered in large systems, can reach thousands of liters.
On the other hand, research shows that it is incorrect to automatically consider air conditioning water as distilled, sterilized, or potable.
The composition varies, and there may be contamination.
Therefore, the greatest potential currently demonstrated lies in the controlled use for non-potable purposes, especially where multiple units can concentrate sufficient volumes to justify a collection system.
The small dripping unnoticed on the wall of a house may seem insignificant. However, multiplied by dozens or hundreds of units operating for months, it reveals a source of water that science is trying to stop treating simply as waste.
