AC Leaking Water? Here’s What to Do

It’s no secret that ACs produce water as a byproduct of cooling your home.

But what may come as a surprise is when your AC leaks water everywhere!

What do you do when your AC leaks and turns your floor into a puddle of water?

In this article, I’ll go over the steps that you should take if your AC is leaking water. I’ll also go over why ACs leak water and how to fix a leaky AC.

What you should do when your AC is leaking water

If your AC is leaking water, it has a drainage issue that you need to fix. The drainage issue is usually caused by a clogged drain line, but could also be due to something else such as the drain pan or drain pump.

Here’s a list of steps that you should take if your AC is leaking water:

  1. Unclog the drain line
  2. Clean the drain pan
  3. Check for a frozen evaporator coil
  4. Change the dirty air filter
  5. Fix the float switch
  6. Fix the condensate drain pump (if your AC has one)

I’ll go over them below.

Unclog the drain line

If your AC is leaking water, the first thing that you should do is check if its drain line is clogged. A clogged drain line will cause water to back up and leak out of your AC.

ACs produce water in normal running conditions. The drain line is there to remove the water from your AC and direct it outside your home or down the drain.

If your drain line gets clogged, then water will leak out of your AC and cause a huge mess.

For more information about unclogging a condensate drain line, check out my article below:

Clean the drain pan

A dirty drain pan may clog up your AC’s drain system, so clean your drain pan if your AC is leaking water.

The primary drain pan is inside your AC and will catch the water as it drips off of your AC coil.

If the primary drain pan gets clogged, then it will overflow and your AC will leak water.

That’s where the secondary drain pan comes into play—a pan underneath the AC unit that catches water if it leaks out of your AC.

If your secondary drain pan has water in it, then your primary drain pan is overflowing. You’ll need to clean out and unclog the primary drain pan and drain line to stop the AC water overflow.

Check for a frozen evaporator coil

A frozen evaporator coil will produce large amounts of water as it thaws out. If your evaporator coil is frozen, you’ll need to let it thaw out, then find the cause of the frozen coil—usually an airflow or refrigerant issue.

A frozen evaporator coil will commonly make an AC leak water as the ice block thaws out. It usually happens because the AC’s condensate drain pipe is already a little clogged—the drain pipe isn’t large enough to accommodate the flow of water from a thawing AC coil.

If your AC’s evaporator coil is frozen, you likely have a larger issue—one that’s beyond condensate drainage.

For more information on how to deal with a frozen evaporator coil in your AC, check out my article below:

Change the dirty air filter

A dirty air filter can cause your AC’s coil to freeze up and leak water when the coil thaws out. A dirty air filter also restricts airflow in your AC and will cause your AC to produce excessive condensation.

It’s well known that a dirty AC filter causes all sorts of problems—water leaks included.

While a dirty air filter won’t directly make your AC leak water, it can cause other problems that will eventually make your AC leak water.

One way that a dirty air filter causes an AC to leak water is through airflow restriction.

The airflow restriction from a dirty air filter causes your AC to subcool the air going through the unit. This makes the AC produce more condensation that has the potential to leak out if your AC drain is slightly clogged.

A dirty air filter will also cause your AC coil to freeze up and will potentially lead to a water leak—which I spoke about in the previous section.

Fix the float switch

The float switch is a device that is used to turn off your AC when it fills up with water. If the float switch is broken, then your AC will leak water if its drain system gets clogged.

Not all AC systems have a float switch. But if your AC does, the float switch should turn off your AC before it starts leaking water.

However, like any mechanical component, a float switch can have issues. Especially if it’s installed improperly.

For more information about AC float switches, check out my article below:

Fix the condensate drain pump (if your AC has one)

If your AC’s condensate drain pump breaks, then your AC will leak water since it won’t be able to drain water on its own.

If your AC has a condensate drain pump, it will leak water if the drain pump stops working.

Condensate drain pumps are usually used when the air handler is installed at a low elevation—such as in the basement.

The purpose of the drain pump is to move the water that your AC produces up to a higher elevation and out of your home.

If the pump breaks, then your AC will start leaking water all over your floor. I recommend giving your pump a good cleaning to try and get it working again. Sometimes condensate pumps will gunk up and stop working.

About Your HVAC Training Shop Author

Hi, my name is Trey Lewis and I’m the founder and chief editor at HVAC Training Shop. My goal for this website is to help homeowners troubleshoot and maintain their home’s HVAC systems. Whether it’s changing an air filter, troubleshooting a blower motor, or just buying a new humidifier, I want to make sure that you’re covered.

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