Water Dripping from an Air Conditioner: Can You Reuse It?

The water dripping from an air conditioner forms when moisture in the air condenses on the cold coil and then runs through the unit's drain. Although it is not safe to drink, this liquid has a low mineral content and can be reused for certain household jobs, including washing floors and cleaning outdoor spaces. The key precaution is not to mistake its clear appearance for drinking water, as it travels through internal components that may contain dust and micro-organisms.

Why does an air conditioner produce so much water on some days?

As the unit cools a room, some of the water vapour in the air meets the cold surface of the evaporator and turns into droplets. The more humid the space and the longer the appliance operates, the greater the amount of water that may be collected. This water flows into a tray before being discharged through the drain.

Because the liquid results from condensation rather than coming directly from the mains water supply, it usually contains few minerals. This makes it suitable for some forms of reuse in tasks that do not involve drinking or personal hygiene.

• Washing floors and patios;
• Cleaning outdoor areas and handrails;
• Washing a car's bodywork;
• Cleaning certain durable surfaces;
• Reducing the use of treated water for straightforward household tasks.

Can air conditioner water be used to water plants?

For ornamental plants, condensation water may occasionally be reused when the unit is clean and the liquid has no odour, colour or visible residue. However, as it contains few mineral salts, it does not provide plants with the nutrients they need and should not permanently replace other water sources and appropriate fertilisation.

Why should it not be used for drinking or cooking?

The water may look clear, but it passes through the coil, tray and drainage pipe before leaving the appliance. Along this route, it may come into contact with dust, biofilm, cleaning residues, metal particles and micro-organisms. It should therefore not be regarded as distilled water that is safe for consumption.

The same care applies to any use where the liquid could come into direct contact with people or animals.

• Do not use it for drinking or cooking;
• Do not wash fruit, vegetables or utensils with this water;
• Do not put it in animal drinking bowls;
• Do not use it in aquariums;
• Do not add it to humidifiers;
• Do not use it for personal hygiene procedures.

How can you store the water without creating another problem at home?

Ideally, the drain should feed into a clean container, preferably one with a lid. Collected water should not be left forgotten for several days, as it may develop an odour, collect dirt and create conditions that encourage insects to breed. The sooner it is reused, the easier it is to manage.

• Use a sanitised container;
• Keep it covered whenever possible;
• Do not leave the water standing for long periods;
• Dispose of the contents if an unusual smell or colour appears;
• Clean the container and drain outlet regularly.

Reusing water also depends on air conditioner maintenance

A clean air conditioner reduces the amount of dust and matter that builds up in the filters, tray and drainage system, but even flawless maintenance does not make condensed water safe to drink. Dirty filters, sludge-filled trays and unmaintained drains are further reasons to restrict its use to tasks that do not involve consumption.

Rather than allowing litres to run straight onto the ground, some of this water can be directed towards cleaning, outdoor areas and certain ornamental uses. Reuse is worthwhile when it follows three simple rules: collect it in a clean container, use it promptly and never drink it. In this way, an unavoidable by-product of the appliance's operation can replace a small amount of treated water in tasks for which it is simply unnecessary.