Why Is My AC Leaking Water? 4 Possible Reasons

September 27, 2024

Have you ever had sudden problems with your air conditioner and then found wet spots around the unit? Did you think to yourself, “Why is my AC leaking water?” You’re not alone—leaking water is a common problem with broken AC units. 

Because HVAC systems involve many parts, the problem could be from the drain pan, the evaporator coil, or even the air filter. To figure out the issue and find a solution, work with a professional technician. At Blue Flame, we provide a variety of AC services to meet whatever your needs are.

Here’s what you need to know about the problem and how a professional will fix it.

4 Reasons Why Your AC May Be Leaking Water

What causes AC to leak water? 

A common problem is improper installation. Thankfully, with Blue Flame’s quality guarantees, you never need to worry about what to do if something goes wrong during this process. We’ll always take care of your home during an air conditioner installation. 

However, issues can happen to any AC unit over time through regular wear and tear. Learn about which parts contribute to leaks and how we can fix them to get your home dry and cool again.

1. Clogged Drain Line or Leaky Drain Pan 

Water drainage is a byproduct of an air conditioner's cooling process. Moist, warm air is pulled into the system, and dry, cool air is pushed out. So what happens to the water? It drips onto the drain pan, which then funnels it into the drain line and out of the home. 

Problems with these parts are the most common reason AC units leak water. Over time, drain pans may hold standing water for too long and develop buildup, such as mildew, that prevents water from draining properly. 

This can be a problem no matter how old your unit is. In old units made of metal, rust could cause breakages or leaks. In new models made of plastic, leaks can still happen as the material degrades over time. To fix the leaking because of a drain pan, your HVAC technician will clean or replace it, depending on the problem. 

Drain lines, on the other hand, can become clogged. This may also be due to the buildup of mildew over time or other impurities in the water. To stop leaks, your technician will flush the drain lines to ensure any clogs clear through the system. 

2. Frozen Evaporator Coil 

When air is pulled into your air conditioner, it cools by blowing over the evaporator coil, which uses refrigerant to absorb the heat from the air. 

When the coil stops working properly for whatever reason, it freezes over, and moisture freezes to it in a buildup of ice. As the system tries to recalibrate, this ice melts, causing an overflow of water to flood the drain pan and leak out into your home. 

Why does your AC leak water? Several issues can cause the evaporator coil to freeze over, including: 

• Restricted airflow, such as from a dirty filter 

• Dust or dirt on the coil 

• Low refrigerant levels 

To fix a frozen evaporator coil, a technician will clean off the coil to remove any ice or dirt. They will then address any underlying causes by replacing the air filter or refrigerant. 

The technicians at Blue Flame are trained to deal with any AC repair need, so we can address both the evaporator coil and the underlying cause during a service appointment.

3. Leaking Refrigerant 

Refrigerant is a key part of your air conditioning system. This chemical is what cools the air, as it absorbs heat. The refrigerant flows through the evaporator coil in a closed system. The refrigerant depends on this closed system to maintain the necessary pressure to absorb heat efficiently. 

If anything disrupts this closed system and causes a leak, the refrigerant cannot cool the air properly. Because of this, even a tiny leak can cause significant issues, such as a frozen evaporator coil and leaking water. 

An HVAC technician can identify where the refrigerant is leaking from or how the levels dropped too low. They’ll repair the part to restore a closed system. Then, to restabilize the system, they will recharge or replace the refrigerant.

Once refrigerant levels are sufficient, the technician will make sure that any other affected parts of the system—such as the evaporator coil or drain pan—are also working properly again.

4. Dirty Air Filter 

Many homeowners have dealt with air filters even if they don’t usually see the other internal parts of an HVAC unit. Replacing filters is an easy DIY maintenance task that keeps your unit working properly. If you’re not familiar with them or haven’t changed yours in a while, be aware that the filter could be the culprit of your AC leak. Dirty air filters can also cause other problems, such as short cycling, so you should replace them regularly.

Air filters are just what they sound like: layers of material that filter debris out of the air as it flows into the HVAC system. They are typically made from fiberglass with filtering coatings in a cardboard frame. 

When working properly, they filter out dust, hair, and other debris so those materials don’t clog up the air system. Many are also designed to filter out smaller particles like allergens, mold, and germs. When they get too dirty, they start to prevent proper airflow. As air sluggishly goes into the system, other parts freeze up or don’t work properly, causing leaks. 

To fix this problem, simply switch out your air filter. You can find which size and type you need by looking at the label on your old filter, which is typically located inside the intake vent. If you need help, a technician from Blue Flame can show you how to replace your filter or take care of this task for you. 

Fix Leaking AC Units with the Help of Blue Flame

Why is your AC unit leaking water? It’s likely an issue with one of these parts. Thankfully, a trained HVAC professional can identify the cause and repair the issue. Blue Flame technicians can fix any of these issues that cause AC units to leak water. To schedule a service for your AC unit, call us at 206-388-5667.

If you have other HVAC problems, such as problems with your heater, we can fix those, too! Take a look at our current offers or contact us for more information.