Air conditioners are essential in hot climates, providing cooling and comfort to our homes and workplaces. Unfortunately, AC units can leak water, causing damage and inconvenience. Fortunately, understanding the causes of AC leaking water can help you identify the issue and take steps to prevent it.

There are many reasons your air conditioner might be leaking water. Here are some of the most common causes:

Faulty Drain Line

The drain line is the first thing to check when your air conditioning system leaks. This pipe takes the condensation from your AC to the outside of your house. If this pipe becomes clogged or damaged, it can cause water to leak into your home.

If you notice water coming from under your A/C unit, check for any cracks or holes in this drain pipe. If there are any leaks, call a professional HVAC contractor to replace the drain line or fix any other problems.

Faulty Condenser Coil

Another common reason an air conditioner might leak is a faulty condenser coil on an outside unit. This coil helps compress the refrigerant to cool down indoor air during operation and release it back into the atmosphere once it’s cooled down sufficiently enough for inside use again.

A faulty condenser coil can cause your A/C system not to work properly or function poorly over time if not repaired immediately.

A faulty condenser coil can often be identified by a puddle of water under your A/C unit when it’s running. If you see this, please call an HVAC contractor immediately.

Frozen or Clogged AC Drain Line

The drain line is the pipe that carries condensation away from your air conditioner. If the drain line is clogged, it can cause water to back up and leak inside your home. To fix this problem, clear out any debris in the drain line and run water through it to test for leaks. If you notice water dripping into your attic or crawl space, there may be a problem with the insulation around your A/C unit. In this case, you’ll need to contact an HVAC professional to have them inspect and repair any damage caused by moisture build-up in your attic or crawl space.

Faulty Insulation

If there’s damage to the insulation around your air conditioner unit, water can seep into your home through any holes or gaps in its casing. A qualified HVAC technician should inspect your insulation professionally and repair it to prevent this from happening again. This damage can be more complicated than you think, so it’s best to leave it up to the professionals who know what they’re doing.

Faulty Condensation Pump

The condensation pump is a component that circulates water through the air conditioner. It’s usually located in the base pan of the unit and can get clogged, which causes leaking and poor performance. If you notice that your air conditioner isn’t running correctly, this is most likely the problem. You can check the condensation pump by looking at it and making sure there aren’t any obstructions in its piping. If there are, remove them and try turning on your unit again. If that doesn’t work, then you might need to replace it with a new one.


ACs are an essential part of modern life. They provide comfort and help us survive the summer heat, but they can also be prone to leaking water if not properly maintained or installed. If you suspect your AC is leaking water, contact a professional to diagnose and fix the problem.

If you think you need an air conditioner service in Louisville, KY, contact our team at Thompson Heating & Cooling today. We can help you with all of your air conditioning needs. We’re your trusted HVAC experts, and we can help you with air conditioning.