Air Conditioning

Why is my Air Conditioner Dripping Water?

air con dripping water

All air conditioners collect a small amount of moisture as part of their normal operation. Aircons cool by passing air through an evaporator coil. As the air cools it loses some of its ability to hold humidity and just like a cold drink left sitting on a warm day water droplets form. When everything is running properly these are collected in a drip pan and depending on the type of air conditioner you have are either pumped safely outdoors or flow down a drain-line.

If your air conditioner is leaking an unusually large amount of water or water is dripping inside your house it is a definite sign that something is not right. There are a number of possible causes for your air conditioner to be leaking and unfortunately, most of them are going to require a professional air conditioning technician to correct.

Keep reading to see the most common reasons your air conditioner is dripping water and what, if anything you can do about it.
Reasons your air conditioner is dripping water you can handle

Of all the possible reasons your air conditioner could be leaking water, there are really only two that you should try to handle on your own. Regardless of the cause, your first step should be to turn off your unit to prevent further damage to your property.

1. The temperature is too low outside

This is normally a problem that occurs in the early and late cooling seasons. If the outside temperature drops below 16 degrees Celsius (60 degrees Fahrenheit) your cooling coils may ice up and cause your AC to leak water as they thaw. Simple solution, turn off your air conditioner in cool weather.

2. A clogged air filter

If your air filter becomes clogged it will restrict the airflow going over the evaporator coils. This will cause them to ice over and just like the case above can lead to water dripping when they thaw. Keeping your filters clean should be a part of your regular home maintenance routine but are easy to overlook. If you see water dripping from your air conditioner check them.
When you need professional help with your air conditioner dripping waterPastedGraphic-2.png

If you have eliminated the causes listed above then you have a more serious problem and should call in a professional air conditioning technician. Again, it is best to leave your unit off until they arrive to prevent further damage to your unit and home.

3. Your condenser pump may be broken

If your air conditioner is located inside the structure it may have a condensation pump to push the water collected outside. If this pump is broken the water will have no way to escape and will build up until it starts to leak. If this is your issue the pump will have to be repaired or replaced.

4. The unit may be improperly installed

When your unit was installed it should have been equipped with a P-trap and vent line to prevent water from being drawn back into the drip pan when airflow causes negative pressure. If these were not installed properly a leak is bound to develop over time.

5. The drain hole is blocked

One of the most common reasons air conditioners begin to drip water is because of a clogged drain line. Dust and debris can collect and eventually clog the drain hole. Once the pan has become full the water has nowhere to go and starts drip over the sides. Blowing out the drain line should be part of the regular servicing of your air conditioning unit.

6. Air leakage

If your ductwork isn’t properly sealed and insulated moist ambient air can be drawn into the system and once mixed with the cooler air in your ducts cause condensation to form. This water eventually has to find a way out and drips develop.

7. Low refrigerant levels

When an air conditioning unit is low on refrigerant its coils will begin to freeze over when it is running. Each time it shuts off this ice will melt and could overflow the drip pan. With time, this type of leak can cause serious structural damage and health issues.

8. Drain line disconnected

If there has been any recent activity around your air conditioning unit the drain line may have been damaged or disconnected. Some types of PVC piping can become brittle and be easily damaged when exposed to high temperatures for extended periods of time and sadly, not all installers are conscientious about properly securing the joints on non-pressurised lines.


As you can see there is a wide range of issues that can lead to your air conditioner dripping water. Some of them only require a simple fix like unclogging the drain hole or repairing a broken drain line. Others, on the other hand, are serious issues that left unchecked can lead to major repairs in your home or the eventual failure of your entire heating and cooling system.

The surest way to avoid most of these issues in the first place is to have regularly scheduled maintenance programme with a qualified AC company. If you believe your air conditioner is developing a problem and definitely if you begin to see water dripping through your ceiling it is time to call in the professionals.

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