August 13, 2021
By Mark Paup

Why Is My AC Leaking? An Iowa Technician Explains

Updated January 19, 2024

If your indoor AC unit is leaking water, you’re probably pretty concerned about its life expectancy. But before you start panicking, you should know that many different issues can explain why your AC is leaking, and, therefore, you can try several potential solutions.

Possible issues causing the leak may include:

  • A clogged air filters
  • A cracked drain pans
  • Low refrigerant
  • A clogged condensate drain line

Let’s take a closer look at each of these issues, as well as what you can do to fix the problem.

Need a Des Moines HVAC technician to repair your AC? Contact Golden Rule to schedule service.

A clogged air filters

A clogged filter could cause your AC to freeze over and leak water when the ice melts.


First, we need to explain the function of an air filter. It catches dust and debris that would otherwise enter your AC system alongside your home’s indoor air. The warm, filtered air then enters your system and blows over an evaporator coil filled with a cold liquid agent that absorbs heat from the air. Once the agent cools the air, it gets pushed back out into your home.

So, when the filter is not regularly changed, it gets clogged with particles, decreasing the amount of warm air entering the AC system and blowing over the evaporator coil. A reduced airflow means there isn’t enough warmth counteracting the coil’s liquid agent, so the coil freezes and ices over.

When the ice eventually melts, the resulting water will fill up the drain pan and overflow.

That’s why you might be seeing a puddle of water around the base of your AC.

How to fix it: First, turn off your air conditioner. Then, take out the filter and inspect it. If it’s filthy and clogged with dust and dirt, you should replace it with a new one. Once you have your new filter in place, give the ice on the evaporator coil time to melt, and then turn your AC back on. If the leaking has stopped, the dirty filter was the issue. On the other hand, if the leaking continues, you may have another problem.

A cracked drain pan

Over time, your AC’s drain pan may develop rust or cracks, which could cause water leaks around your indoor AC unit.

The drain pan catches the condensation that drips off the evaporator coil. Since drain pans are always wet, it’s common for them to develop rust and cracks, especially if the AC is more than 12 years old.

If your AC’s drain pan has cracks in it or it’s rusted, the water may be leaking out of it and forming a puddle around the base of your indoor unit.

How to fix it: Unfortunately, since the drain pan sits right underneath your AC’s evaporator coil, you could accidentally damage the coil by trying to replace it yourself. It’s a good idea to call in the pros and have an experienced HVAC technician replace the drain pan for you.

Low refrigerant

If your AC is low on refrigerant, the evaporator coil can freeze over. When the ice melts, the water drips into the pan, and it may overflow.

During an AC refrigerant leak, the amount of refrigerant in the system will decrease, and your AC’s pressure will drop too. As the pressure decreases, so does the temperature of the refrigerant. The already cold refrigerant in the evaporator coil gets even colder and may freeze over when this happens. Eventually, the ice melts, and the water will dip into the drain pan, which will likely overflow and leak water everywhere.

So, if you see water pooling around your AC unit and you hear a bubbling or hissing noise, your AC has a refrigerant leak.

How to fix it: If you suspect your AC has a refrigerant leak, you’ll want to call an HVAC professional. Refrigerant is toxic, so don’t try to seal a leak yourself. Instead, a technician will have the skills and experience to safely repair the leak and refill the refrigerant to the proper levels

A clogged condensate drain line

If dust and debris get lodged in the condensate drain line, the drain pan will overflow with water, pooling around your indoor unit.

A clogged condensate drain line is a frequent cause of AC units leaking. Usually, you can tell if this is the problem because the AC is equipped with an automatic shutoff if it detects a clog. When you see water leaking from your AC and then it suddenly shuts off, that means you’re probably dealing with a clogged condensate drain line.

How to fix it: Try using a wet/dry vacuum to clear the clog from the drain line. Or, if you’re not comfortable doing that on your own, you can contact an HVAC professional to clear the clog out for you.

Need a reliable HVAC technician near Des Moines?

Contact Golden Rule today to schedule service. We’ve proudly served the Des Moines area for more than two decades, and you can count on us to quickly get your AC back up and running with fast and convenient AC repair. Or, if we can’t fix it, we will help you replace it.

Contact Us Today for Heating & Cooling Service!

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