Why Is My Air Conditioner Leaking Water? A Phoenix Tech Answers

If you notice a pool of water near your indoor AC unit, your air conditioner is probably leaking water.

If you live in Arizona and it’s monsoon season, your air conditioner is most likely leaking because you have a clogged condensate drain line.

However, there are several other reasons your air conditioner could be leaking water, like:

So how do you know which one is your particular issue? Below, we’ll walk you through how to determine the cause of your AC leakage and most importantly, how to fix that leak.

But first, let’s look at why and how your air conditioner forms water.

Your air conditioner actually has two jobs: to cool your home and to remove humidity.

Here’s how it works:

Step 1: AC pulls in hot, humid air from your home. That warm air then passes over a very cold evaporator coil.

Step 2: Moisture from the hot air collects on the evaporator coils and eventually drips down into the drain pan.

Step 3: The water in the drain pan drains outside via the condensate drain line.

Now that you know how (and why) your AC forms water, let’s talk about some of the possible problems that can interrupt this process and cause water to leak from your AC unit.

Unfortunately, condensate drain lines are prone to clogging.

Think about it. Your drain line is dark and wet all the time—the perfect conditions for algae, mildew, dirt and other bacterial build up.

If your condensate drain line is clogged, all that water that's supposed to be flowing outside backs up. And eventually, the drain pan will overflow and leak water around your AC unit.

In the summer, when the weather is more humid, your AC is pulling more moisture out of your home. This can make clogs more frequent, resulting in the leak you’re experiencing.

Step 1: Locate your condensate drain
The condensate drain line is a thin PVC pipe that connects to the drain pan and travels outside. You’ll find the end of your drain line outside, usually near your outdoor AC unit.

Step 2: Attach a wet/dry vacuum to the end of the drain
Ensure that the hose has a tight seal on the condensate pipe or it won’t be as effective. Turn the vacuum on for about 3 minutes.

If this doesn’t work, it’s time to call a professional. You don’t want to risk damage to your AC system by trying to unclog a serious blockage.

For more detailed steps on how to clear your condensate drain read our blog, “What Do I Do if My Air Conditioner’s Drain Line is Clogged?”

As we mentioned above, the drain pan catches moisture as it drips off the evaporator coils. If your drain pan is old or rusting, it can develop leaks and holes, which allows the water to leak out onto the floor around your AC unit.

The fix: Call a professional.

If your drain pan is leaking because of a hole, a professional will need to come and replace the drain pan.

Refrigerant is the substance that flows through the evaporator coil and takes the heat out of the air in your home.

However, if refrigerant levels are low, the moisture that collects on your evaporator coil can freeze, building a layer of ice. When the ice on the evaporator coil starts to melt, it can leak onto the floor around your AC unit.

The fix: Call a professional.

If your refrigerant levels are low, it likely means there is a leak in your refrigerant lines. A professional will need to come to your home and fix this issue.

If your AC filter isn't replaced regularly, it will eventually clog. And a clogged filter reduces the airflow to your AC unit.

Over time, reduced airflow can cause the moisture on the evaporator coil to freeze.

If enough ice on the evaporator coil melts, the drain pan overflows and leaks water onto the floor.

Like we mentioned above, ice on the evaporator coil can melt, overflowing the drain pan and spilling onto the floor around your AC unit.

The fix: Replace your air filter

Start by turning your AC off for a few hours to let the ice thaw out. We would suggest putting a few towels around your AC so water doesn’t leak across your floor. Once the ice has thawed, try removing your old, dirty filter and replacing it with a new, clean filter. If your AC stops leaking, this is likely your issue.