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Why is my air conditioner leaking water? 6 common reasons



When the summer heats up, an A/C system helps to keep your home cool and comfortable by lowering temperatures and removing humidity from indoor air. Central A/C systems not only add value to your home, but they also help prevent mold from developing inside the home in humid environments. Comfortable air also helps us focus and may reduce asthma and allergy symptoms. 

While your air conditioning unit is working hard to cool your home, it may occasionally have an issue that needs to be addressed. One of the most common issues with home HVAC systems is water leakage. 

In this article, we discuss some of the common causes of water leakage and what you can do to address the problem when it occurs. 


What to do if your A/C is leaking water

At the first sign of water dripping or leaking from your air conditioner, homeowners should immediately turn off their unit and contact an HVAC technician. If the A/C continues dripping water or leaking for a longer period of time, you may do more damage to the unit. Simply placing a towel down to clean up the leaking water won’t fix the problem. 

Many A/C repairs are not terribly expensive, but one sure way to increase the likelihood of a high-cost expense is to ignore the problem. Leaking air conditioners can cause water damage to your ceiling, walls or floors that go unnoticed at first. Your A/C leaking could indicate an oncoming problem with your compressor, which may lead to replacing the entire unit.   

If you’ve had the foresight to get a home warranty, now is the time to engage with them. If you have a Cinch home warranty, you can easily submit a service request through their online portal, and an HVAC professional will be sent to your home to address the issue. 


6 reasons your air conditioner is leaking water

If you’re troubleshooting an A/C water leak, it's helpful to understand some of the most common causes. Some fixes are pretty simple, like changing out the air filter or adding refrigerant. 

However, clogged condensate drain lines, broken drain pumps, rusted-out drain pans and frozen evaporator coils may also be the culprit. Below we’ll share how each of these issues can lead to a leaky air conditioning unit. 

Clogged condensate drain line

If your A/C is leaking water inside the home, one of the most likely causes is a clog in the condensate drain line. Condensate lines can become clogged over time due to taking in dust and other particles from the air. The dust and dirt stick to the walls of the line creating a blockage that prevents the system from properly draining water. As a result, excess water comes out inside the home rather than outside into the drain pan. Indoor water can do damage to the home and can also lead to mold, so taking care of this problem quickly is critical to avoid more expensive issues. 

Homeowners can help mitigate issues with the condensate drain line by getting regular A/C tune-ups, which includes clearing the lines. Even if the system is not yet leaking water, a clear drain line can improve the overall efficiency of the HVAC system. 

Broken condensate drain pump

A failing or broken condensate pump can also cause a leak in an air conditioning system. The pump itself may still be functioning, but a drainage problem can cause water to build up and spill over faster than the pump can evacuate it. If the pump has completely shut down, however, it will cause a water leak as it is needed to move the water through the system. 

A professional A/C repair person can determine if the condensate pump has failed temporarily or has broken and will need to be replaced. 

Frozen evaporator coils

Another common cause of A/C water leaks is a frozen evaporator coil. The evaporator coil cools the air by vaporizing liquid refrigerant to cool the air. The coils are designed to cool the air inside the system to around 40 degrees, but when there is an airflow problem, a clogged drain, a malfunctioning fan or dirt and dust buildup on the coil, the system can freeze and create ice around the coil. 

When this happens, it is critical to shut down the system and allow it to ‘defrost’ for a while. Closing up too many of your A/C registers can also cause an evaporator coil to freeze up. Try to be sure to have at least half of your register opened to reduce the potential for this problem to occur in your home. 

Dirty air filter

Most homeowners are aware that their air filters need to be replaced monthly for better air quality. They may not realize that a dirty filter can also cause their A/C system to leak water. 

The air filter is designed to capture dirt and dust, so it’s no surprise that they can build up and restrict airflow. The evaporator coils we mentioned above require an adequate supply of air to work properly. A blocked air filter will prevent an adequate supply of air and cause the air inside to get too cold, causing it to freeze, the system to back up and water to accumulate and leak. 

Dirty air filters are perhaps the easiest issue to correct. Sticking to a monthly schedule of replacing them can save you the headache and expense of a larger A/C problem. 

Low refrigerant level

When refrigerant is too low, either from normal usage or a refrigerant leak, you may first notice that your A/C is putting out hot air or warm air instead of cool. You may also hear strange sounds like hissing or bubbling from inside the unit.

The lack of refrigerant can lower the pressure inside the system, which reduces its ability to properly run water out of the system causing the A/C to leak. Low levels of refrigerant in the system also mean your evaporator coils don’t have enough liquid to convert the hot air to cool vapor which can cause them to freeze up over time. When the frozen coils heat up again, they melt and create a leak inside the unit. 

The sooner you identify a low refrigerant problem, the better. Not addressing the problem can damage the A/C permanently and may require you to replace the unit entirely. Your levels should also be checked at least once a year before summer with your standard air conditioner maintenance check. 

Rusted or damaged drain pan

Another cause of an A/C leak is a rusted-out or damaged drain pan. Older units are more likely to have a rusty drain pan, but drain pans can also crack before rust sets in. Both rusted or damaged drip pans will cause a leak that needs to be repaired before the water damages the A/C unit, walls, ceilings or floors. 

Drain pans can also collect gunk that makes the pan overflow. Turn off the thermostat as soon as possible to prevent a larger and more expensive repair to your home or A/C unit.  


How much do A/C system repairs cost?

A/C system repairs typically cost between $160 and $680 for the most common fixes. However, bigger repairs vary significantly based on the type of A/C system, location, parts needed or service provider. 

Let’s break down the cost for repairing an A/C system with water leakage. 

Typical repair costs by issue

  • Clogged drain line. Fixing a clogged drain line will typically cost from $75 - $300 if a replacement line is needed.
  • Condensate pump. Fixing the condensate pump will typically cost between $250 - $500. 
  • Drain pan. If a drain pan is rusted and needs to be replaced, the cost typically ranges between $200 - $600. There may be an option to repair the drain pan if it is cracked rather than rusted, which may help keep you on the lower end of the repair cost. 
  • Evaporator coil. On the more expensive side of leak repairs is replacing the evaporator coil. This is a more labor-intensive job that requires approximately eight hours to complete, putting the cost somewhere between $600 and $2000
  • Condenser replacement. To replace your A/C condenser, you’ll be looking at a cost between $1000 - $4000 including parts and labor. Your cost will depend on your unit type and will typically take around four hours to complete. In some cases, it may be wiser to simply replace the unit altogether. 
  • Dirty air filter. Replacing a dirty air filter should be done monthly and may not require a technician to complete it. Air filters cost from $25 - $85 per piece.  
  • Low refrigerant level or refrigerant leak. The cost to fix your A/C unit’s refrigerant leak can range from $225 to $1,600 depending on where the leak is located and the severity of the leak. Some leaks can take longer than eight hours to identify and recommend a course of action. 

When to repair and when to replace your A/C Unit

Central A/C systems cost more to repair than a window unit as they also include ductwork, which can cost between $2,500 - $7,000. Prices differ depending on the power and size of the unit needed to cool the space. If you need ductwork installed you can expect your cost to be in the $6,500 - $12,500 range. 

We recommend you replace your system in these circumstances:

  • The unit is over 10 years old and needs major repair work.
  • Repair is over $5,500 when you multiply the cost of repair by age of the system. 
  • Repair cost is more than 50% of the cost of a new unit.
  • The system uses a phased out coolant like R-22 Freon.

How to find the best A/C service technicians in your area

When it’s time to find a service technician, you’ll want to be sure to choose a licensed and certified provider who provides service in your area. 

You can start by looking for reviews online. Sites like Angi or Yelp offer a platform of customer reviews that can give you a sense of a company’s level of service. Check to see that reviews are recent and check out both positive and negative reviews for a fuller picture. 

If there are only a few reviews available on the platform, try searching again elsewhere online, like on the company’s Facebook page. You can also check to see if a business has a Better Business Bureau (BBB) rating. Your state business registration website can also tell you how long a company has been in business and helps ensure the provider you’re considering is following best practices. 

Searching Google for a specific business name may also return reviews from Google Business (usually found along the right-hand side of your computer or at the top of the returns on your smart device) that will also provide locations, hours of operation and contact information. You can also search your A/C manufacturer's website for out-of-warranty repair providers or see if an issue is covered under a valid warranty. 

Cinch customers can quickly and easily get a vetted and certified A/C technician for service by submitting a service request online or by phone. 


A/C units are covered under a Cinch warranty

If you’re looking for a way to mitigate potential high costs of A/C repairs and have easy access to reliable A/C technicians, consider investing in a Cinch Home Services Built-in Systems plan. Cinch built-in systems warranties cover both normal wear and tear and ductwork repairs that are typically not covered by home insurance. 

A Cinch home warranty offers affordable solutions for maintaining home systems that bring homeowners protection from unexpected and expensive repairs and peace of mind when things go wrong. Get a quote on a Cinch protection plan today!


Learn about the six most common reasons your A/C is leaking water in your home.