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Why Is My AC Leaking Water? A Phoenix Tech Answers

April 28, 2020

If you see puddles of water around your AC system, more than likely, something is not right. And you’re probably concerned about water damage to your home, so you want the problem fixed quickly.

Don’t worry—we’ll help you troubleshoot this frustrating AC problem.

In this blog, we’ll explain what causes an AC to leak water, depending on where you notice the leak (inside or outside).

Want a Phoenix pro to quickly repair your AC? We offer 24/7 service and emergency repairs. Call (602) 280-1793 or schedule an appointment online.

Is the leak inside? Here are 3 reasons why

If you see a puddle of water near your indoor AC unit, you may have one of the following problems:

  1. A frozen evaporator coil
  2. A leaky drain pan
  3. A clogged condensate line

Let’s look at each of these possible causes in more detail.

Cause #1: A frozen evaporator coil

The evaporator coil is the part that essentially cools your home’s air. It’s located inside the air handler (the indoor unit of your air conditioning system).

The evaporator coil of a central AC system

Passing through the evaporator coil is refrigerant, which is a substance that absorbs heat from your home’s warm air. When the refrigerant absorbs heat the air becomes cooler. This cold air is then blown into your home to lower the indoor temperature.

However, some situations cause the refrigerant to get very cold, which ends up forming ice on the evaporator coil.

A frozen evaporator coil is caused by the following issues:

  • A refrigerant leak: If refrigerant levels are low because of a leak somewhere in the system, then the temperature of the refrigerant will drop, causing the coils to freeze over.
  • A dirty air filter: A clogged air filter prevents warm air from blowing over the evaporator coil, which can cause the refrigerant to get too cold and freeze the coils.
  • Closed or obstructed vents: Similar to a clogged air filter, closed or obstructed air vents could be blocking airflow over the evaporator coil, which can eventually cause it to freeze over.

Solution: First, check your air filter to see if it’s dirty. If it is, replace it with a clean one. Second, make sure all of the supply vents (where air comes out) in your home are open, and that no furniture or curtains are blocking the return vent (where air goes into your AC system).

If those 2 quick DIY fixes don’t stop the leaking, you’ll need to contact a professional to determine why your evaporator coil is freezing over.

Cause #2: A leaky drain pan

The drain pan sits beneath the evaporator coil in your indoor unit. The purpose of the drain pan is to collect condensate that forms over the coils. Eventually, this condensate exits your home via the condensate line (which we’ll explain in more detail below).

Sometimes the drain pans can become rusted, which causes the condensate to leak out and form puddles around the air handler.

Solution: Contact an HVAC pro to replace your drain pan with one that fits your AC model.

Cause #3: A clogged condensate line

Under normal conditions, your air conditioner will drain condensate that forms on the evaporator coils out of your home via a drain (condensate) line. This drain line runs from the air handler to the outside of your home.

However, if the drain line is clogged, water will back up into the drain pan and eventually overflow.

When the condensate line is clogged, water can overflow from the drain pan

Solution: If you feel up to the task, you can attempt to remove the clog yourself by connecting a wet/dry vac to the outside end of the condensate line. Turn on the vac to remove any debris clogged in the pipe.

If that doesn’t solve the problem (or you don’t have the time to fix it yourself), contact an AC pro to clear the clog for you.

Is the water leaking near the outdoor AC unit?

While it’s normal to see a small amount of water near your outdoor unit, if you notice a lot, it may be because...

  • It’s an especially warm or humid day
  • The evaporator coil is frozen
  • There’s a refrigerant leak in the outdoor unit

Cause #1: It’s an especially warm or humid day

When the weather is especially hot and humid, your air conditioner pulls more moisture out of your home’s air. This condensation will drain out of your home via the condensate line, which would explain why you’re seeing more water than normal around the outdoor unit.

Solution: If the weather is the culprit, there’s really nothing wrong—your air conditioner is working just fine and there’s no need to contact a professional.

Cause #2: The evaporator coil is frozen

If extreme weather isn’t the explanation but you’re seeing a lot of water pooled around the outdoor drain line, the most likely explanation is that you have a frozen evaporator coil.

When the ice on the evaporator coil eventually melts, all that water will drain outside (if the condensate line isn’t blocked as we mentioned above). That could explain why you’re seeing a large pool of water around the outdoor unit.

Solution: You’ll need to contact a professional to make sure your evaporator coil isn’t icing up. Besides the leaking water, a frozen evaporator coil also creates problems like higher energy bills and warmer indoor temperatures.

Cause #3: There’s a refrigerant leak in the outdoor unit

Earlier we talked about refrigerant, which is the liquid/gas substance that removes heat from your home’s warm air, outside.

In its liquid form, refrigerant looks similar to water. If you notice a large amount of liquid around the outdoor unit, it could mean refrigerant is leaking from the compressor, condenser coils or one of the refrigerant lines.

If you have a large refrigerant leak, you’ll definitely notice. You may hear a hissing sound and your home won’t feel as cool.

Solution: Since a refrigerant is a potentially harmful substance to humans, it’s best to let a certified professional find and fix any refrigerant leaks. Contact a professional to inspect your outdoor unit and make sure there are no leaks in the outdoor unit.

Need an AC repair from a trustworthy Phoenix technician?

Call (602) 280-1793 or schedule an appointment online. Our highly trained technicians can quickly find and repair whatever is causing your AC to leak water.

For more information about what to expect when you hire us, visit our AC repair service page.

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By Ty Lindsay

Ty Lindsay is the Director of Field Operations at Patrick Riley | Isley’s and a 15-year veteran of the plumbing and HVAC trades. In 2010, Ty earned his Journeyman’s plumbing license. He became a Master Plumber five years later and earned his Journeyman HVAC technician’s license that same year. Ty’s breadth of knowledge in plumbing and HVAC includes both residential and commercial work. He’s been a loyal member of the Patrick Riley | Isley’s team since 2016.