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How to Fix Air Conditioner Leaking Water Inside


There’s nothing more frustrating than coming home on a scorching summer day only to find your AC leaking water inside your house. Not only is this an inconvenience, but it can also lead to costly damage to your home if left unaddressed.

If you’re facing this problem, don’t worry; you’re not alone, and there are steps you can take to diagnose and fix the issue. Here, we’ll guide you through identifying the causes of an air conditioner leaking water inside and offer solutions to fix your air conditioner immediately.

Why Is My Air Conditioner Leaking Water Inside the House?

ac leaking water

Is your AC leaking water inside your home, but don’t know why? There are multiple reasons as to why you have a leaking AC unit.  Here are some common causes:

Clogged Drain Line

A clogged condensate drain line is one of the most common reasons for an air conditioner water leak. An air conditioner circulates warm air flow, passes it through a refrigerant, and blows out cool air.

In an air conditioning system, the condensate drain line carries the water that forms during the cooling process out of your home. If it’s clogged or disconnected, the moisture may not escape, leading to water leaking inside the AC unit. 

Dirty or Clogged Air Filter

If your air conditioner is leaking water, sometimes it’s because of a clogged or dirty air filter. Leaving an AC running with a dirty filter causes air conditioner leaks. It can reduce the airflow over the evaporator coils, causing them to freeze and thaw. 

Regularly changing or cleaning your air filter is essential for maintaining your air conditioner’s efficiency.

Dirty or Frozen Evaporator Coil

Dirty or frozen evaporator coils can also be a culprit. When the evaporator coil is covered in dirt or ice, it can impede the heat exchange, create excess condensation, and cause your AC to drip water. 

This excess water can then drip from the unit and cause your AC unit to leak water.

Broken Condensate Pump

A broken condensate pump can lead to water leaks from your air conditioner, posing a risk of potential water damage to your home. The condensate pump is essential for removing the condensate water produced during the cooling process, and when it malfunctions, water can accumulate and overflow from the AC unit, causing leaks. 

Common causes of a broken pump include mechanical failure, clogs or blockages, power issues, float switch problems, and wear and tear due to the pump’s limited lifespan. 

Damaged Drain Pan

Air conditioners remove moisture from the air as part of their cooling process. This moisture, also known as condensate, usually collects in drip pans or drain pans and is drained away safely. When you see water leaking inside your home, it indicates that something is amiss. 

The drain pan underneath the evaporator coil is designed to catch condensate and guide it to the drain line. If you have a rusted drain pan or misaligned pan due to damage over time, it might cause water leakage. 

Refrigerant Leak

A refrigerant leak can lead to a drop in temperature inside the evaporator coil; this, in turn, causes the pressure inside your AC units to drop. The decrease in temperature would lead to a frozen coil.  

The frozen coil would then form ice around itself and its surroundings. Once the ice melts, water forms due to excessive moisture, which causes water accumulation and AC leaks. To put it into perspective, it’s just like a cold glass with water dripping from it due to the hot air. 

You might have this problem if you hear a bubbling noise or hissing sound accompanied by AC leaking water. It’s best to contact an AC repair expert as soon as possible to prevent further damage to your air conditioning unit.

High Indoor Humidity 

In areas with high humidity, like the Philippines, your air conditioner may have to work harder to remove moisture and warm air.

This can result in increased condensation and the potential for leaks if the drainage system is not handling the extra moisture effectively.

Improper Sizing and Installment

Leaking air conditioners are sometimes caused by improper installment and sizing. An AC unit that is too large or too small for its cooling space may experience operational issues, including excessive condensation and water leaks. 

Another example is when your pipes are not precisely sized, it will disrupt the water flow from your drain line to the drain pan. Proper sizing and installation are crucial to avoid these problems.

Now that you know why your air conditioner is leaking water, let’s explore how to address and fix the issue.

How Do I Stop My Air Conditioner From Leaking Water Inside?

Water dripping from your AC system is not just an annoyance; it can be a sign that your air conditioning unit has an underlying issue that, if left alone, would hinder the AC’s performance. 

Now that you understand why your air conditioner is leaking water let’s discuss how to fix the problem:

Check the Condensate Drain Line

Begin by turning off the power to your air conditioner before attempting any maintenance. Locate the condensate drain line, typically a PVC pipe extending from your air conditioner to the exterior of your home.

Inspect the drain line for any obstructions or accumulated dirt. Using a wet/dry vacuum or a long wire brush, you can effectively remove debris. To clear any remaining clogs, pour a mixture of equal parts water and vinegar down the drain line. This will help ensure proper drainage and prevent further leakage.

Modern air conditioners typically have a “shutoff” trait that detects when there is a clog in a drain pipe. If you don’t have a modern air conditioning system, you can use a drain cleaner or pour bleach every six months as maintenance.  

Clean or Replace the Dirty Air Filter

First, ensure you turn off the AC’s power for safety. Next, locate the air filter within the air handler unit and thoroughly inspect it. If the filter is dirty or clogged, replacing it with a new one is advisable.

Some telltale signs that your air conditioning units’ air filters are dirty are that they blow warm air, you have higher utility bills, and your AC system is short cycling. 

If the filter is designed to be reusable, you should clean it meticulously to maintain proper airflow and prevent future issues. You can use a soft brush to brush off the dust and dirt accumulated in the filter. 

Regular maintenance is crucial to prevent dripping water and the freezing of the evaporator coils.

Ensure Proper Drain Pan Function

First and foremost, turn off the AC’s power to ensure safety during the inspection and potential repairs. After that, locate the drain pan situated beneath the evaporator coil. This drain pan is crucial for collecting and directing condensate to the drain line.

Inspect the drain pan thoroughly for any cracks, rust, or signs of misalignment. If you discover any issues, it’s essential to promptly address them by repairing or replacing the pan as necessary. 

Proper functioning of the drain pan is vital in preventing water leakage inside your home.

Check the Evaporator Coil

First, turn off your air conditioner to let the coils thaw if frozen. Then, inspect the coils for dirt and debris and clean them carefully using a soft brush or compressed air. 

To prevent future issues, change your air filter regularly, maintain good airflow around the evaporator coil, and consider scheduling regular professional maintenance to keep the coils clean and in proper working condition. 

If the coils are excessively dirty or damaged, it’s advisable to consult a qualified HVAC technician to assess and address the situation effectively.

Check the Condensate Pump

First, turn off the power to the air conditioner, access the pump, and inspect it for visible damage, loose connections, or clogs. Clean the pump and remove any obstructions, check the float switch for obstructions or damage, and test the pump’s operation by adding a small amount of water to its reservoir. 

If the pump remains nonfunctional or is damaged beyond repair, consider replacing it with a new pump that matches the specifications of the old one. Ensure proper installation and follow the manufacturer’s guidelines. 

To prevent future issues, perform regular maintenance on the condensate pump, and if in doubt, seek professional assistance from an HVAC technician for thorough diagnosis and repair.

Buy a Humidifier

To fix high indoor humidity, use a dehumidifier to remove excess moisture and maintain humidity levels between 30-50%. Ensure proper ventilation through exhaust fans in kitchens and bathrooms, open windows on low-humidity days, and keep your AC system for efficient dehumidification. 

Address leaks and maintain gutters to prevent moisture ingress, insulate and seal your home to keep humid air out, and check for condensation to identify trouble spots. Avoid overwatering houseplants, limit indoor drying, and store firewood outside to mitigate moisture sources. 

Monitoring indoor humidity with a hygrometer will help you fine-tune your efforts for a more comfortable and moisture-controlled living environment.

Call a Professional

If you don’t want your AC to leak water but don’t have the time to fix it, contact an HVAC technician; they can quickly pinpoint the root cause.  

Contact a professional HVAC technician for refrigerant leaks, misaligned installments, or broken condensate pumps. Attempting to fix complex unit leaks without expertise can lead to more damage.

Can I Still Use My AC If It’s Leaking Water?

If your air conditioner is leaking water inside, it’s best to turn it off until you can resolve the issue. Continuing to use a leaking AC can lead to more extensive damage to your unit, your home, or both. It may also compromise indoor air quality and expose you to mold or mildew growth. Turning off the AC will prevent further water leakage and potential safety hazards.

Final Thoughts

A leaking air conditioner is a common problem with multiple potential causes, from clogged drain lines to dirty air filters. It’s crucial to address the issue promptly to prevent further damage to your cooling system and home.

Always turn off your AC if it’s leaking, and consider consulting a professional for complex issues. With regular maintenance and timely repairs, you can enjoy a cool and comfortable home without the hassle of water damage.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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