When the weather outside is hot, you want your home inside to be comfortably cool. Yet, seeing your air conditioner leaking can be unsettling as it means something is wrong. Dealing with an air conditioner leaking water inside your home can also lead to bigger problems if left unchecked. The last thing you need is a leaking AC unit that might cost you big bucks in HVAC repairs.

An air conditioner leaking water outside or inside can indicate a serious issue, but there is no need to panic. Learning how to fix a leaking air conditioner is easier than you think, and it may not require expensive repairs from a technician. In this guide, we'll discuss the common problems that can result in your AC leaking water and show you how to fix a leaking air conditioner.

Why is My Air Conditioner Leaking Water Inside?

The best way to understand how an air conditioner works is to think of your unit as the refrigerator for your house. Just like your refrigerator, AC systems do not produce cold air. Instead, your AC unit cools your home by removing heat and humidity from the air.

Every air conditioning unit has evaporator coils. When your HVAC unit draws in the warm air from your home, it is blown over the cold evaporator coils causing it to condense, which helps make your home less humid. This moisture ends up dripping into a drain pan and draining through the condensate drain line that leads out of your home.

When you see your air conditioner leaking, there is usually a reason why excess water vapor is accumulating in your air conditioner, making it difficult for the system to remove the extra water.

Ways to Fix a Leaking Air Conditioner

From checking air filters and drainpipes to pumps and pans, there are many ways to identify and solve your AC leaking water. Here are four areas to check and corresponding solutions to try, before making the call to an HVAC expert.

1. Blocked Drain Line

This is a good first place to check as a clogged condensate drain line is one of the most common reasons for a leaking air conditioner. The water collected by your air conditioner contains dirt and debris. The drain line can become blocked by that debris and even by mold or algae growth, causing water to back up and overflow inside your home.

Solution: Unclog the Drain Line

Turn off your AC unit at the thermostat and flip off the circuit breaker for the system, then locate the drain pan to check for standing water. Use a wet/dry vacuum to remove the standing water and thoroughly clean the drain pan to prevent mold growth.

Next, find the drain line and check if it is clogged. If there is a clog, you need to clean the drain line. To do this, locate the drain line at the base of the unit and remove the cap. Use a wet/dry vacuum or a pipe cleaner to suction out any blockages in the drain line.

Once unclogged and clean, you can also pour a mixture of vinegar and water down the drain line to kill any algae or mold growth that may be causing the blockage. Rinse thoroughly by pouring a small amount of clean water through the line and make sure it seamlessly flows out of your house.

Pro tip: As a preventive measure, focusing on regular HVAC maintenance should be on your priority list.

A clogged condensate drain line can lead to a leaking AC unit

2. Damaged Condensate Drain Pan

The condensate drain pan collects water and is located underneath your AC unit below the evaporator coils. While a simple job, the drain pan can still become damaged or corroded, causing water to leak from the unit. Water vapor is supposed to flow into the drain line and outdoors. However, if the drain pan is damaged or rusted, the water will start to leak from the pan instead of traveling down the drain line.

Solution: Seal Cracked Drain Pan or AC Drain Pan Replacement

If you have a cracked drain pan, it will need to be carefully and securely resealed to prevent your AC leaking water. First, don safety goggles and clean the drain pan well using a bleach and water mixture to fend off algae and mold.

Next, pour water to help identify any cracks as the water runs. Once you identify any cracks, use a high-quality water-resistant sealant to seal the cracks. After the proper cure time, test the seals by again pouring water on the pan and see if leaks still occur. Repeat until there are no more leaks.

If the drain pan is rusty and beyond repair, then you will need to do an AC drain pan replacement. But it is not as simple as taking out the old pan and sliding in a new one. It must be the right size for your unit to work efficiently. If you have a hard time finding the correct size pan or find it difficult to replace, contact a professional HVAC to assist in finding and installing the appropriate one.

3. Clogged Air Filter

One of the most common causes of a leaking air conditioner is a dirty or clogged air filter. The filters ensure proper air circulation and allow clean air to enter your house. However, particles and dust accumulate on the filters and clog them completely over time. A dirty air filter will restrict airflow and cause the evaporator coil to freeze up, leading to excess condensation and water leakage.

Solution: Replace Air Filter or Clean It

First, turn off the power to the AC. Next, clean up any standing water with a vacuum or towels to best protect your walls and floor. Then, remove the panel that houses the air filter and inspect the filter to see if it needs to be cleaned or replaced with a new one.

If you have a washable air filter, first brush it lightly with a rag into a garbage bag to capture any gunk or debris. Then, rinse the filter under lukewarm water before letting it dry completely. Once dry, put it back in your unit facing the appropriate direction of airflow. (Look for arrows on the filter frame to place it back correctly.)

If you have a replaceable filter, then an air filter replacement is what you need. Simply head to your nearest hardware or box store to find your replacement filter. Be sure to choose the correct size and type of filter for your unit, or your system will not filter properly.

Changing air filters regularly help prevent a leaking air conditioner

Pro tip: When you find the right size of filter for your system, write it down and keep it as part of your home maintenance manual for easy and quick reference.

Home Warranty tip: Regularly changing your filters is a great way to keep your air healthy and help reduce your energy bills. With a First American home warranty, you can take advantage of a convenient, easy way to get new air filters shipped free to your door through a Filterjoy subscription.

4. Frozen Evaporator Coil

As mentioned before about clogged air filters, airflow is important to an air conditioner’s functionality. One reason airflow is important is it allows warm air to flow over the evaporator coils and helps prevent coils from freezing up. If the evaporator coil becomes frozen, it can create excess condensation and cause a leaking AC unit.

Solution: Clean Air Filter and Thaw Coils

The first step is to turn off the unit and allow the evaporator coils to defrost completely. While the coils defrost, take out the air filter and clean as stated above. Once the coil is defrosted, clean any standing water and replace the newly cleaned or new air filter. Turn the unit back on and monitor it over the next few hours to ensure that it's not freezing.

Pro tip: Another reason your coils may freeze is due to low refrigerant. If there is not enough refrigerant to run through the system, the coils become too cold and can easily freeze. Contact a professional to add refrigerant and ensure that there are no leaks in the system.

First American HVAC Coverage

Learning how to fix a leaking air conditioner is not in everyone’s wheelhouse. If you’re worried about potential problems that can arise with home systems such as your HVAC, invest in a home protection plan that includes HVAC coverage to protect your budget when breakdowns happen. First American offers plans that can cover many major home appliances and systems, including your air conditioning unit. Learn more about what our home warranties cover and get a home warranty quote.