How To Fix HVAC Leaking Water?

This summer has been scorching for those living in the north-western hemisphere. The U.K. hit several record high temperatures across the country. The U.S. has had several droughts, with temperatures breaking 100 degrees Fahrenheit (38 degrees Celsius) across the board. So, if you notice your HVAC unit leaking, you’ll want to fix it immediately! 

To fix your HVAC unit leaking water, you’ll first have to identify the cause. It could be damaged pipes, clogged pipes, or old and dirty air vents. To fix these leaks, you’ll need to remove the damaged parts and replace them with new ones. Experts should do some repairs to ensure proper care. 

If you’re hoping to fix your unit, you came to the right place. I’ll help you identify the cause and give you the best solutions. Last, I’ll let you know when to call in the experts!

1. Unclog Drain Pipes

The drain pipe is sometimes also called the condensation relief pipe. It is typically a 4-7 inch (10.16-17.78 cm) drain pipe outside a house or building. However, the pipe also runs throughout the house and can leak at any point. 

AC units remove moisture and humidity from the air to make for a more comfortable living environment. The drain pipe collects this moisture and moves it outdoors. 

Debris collecting inside the pipes can disrupt the water flowing through them. As the water becomes lodged inside, it may create pressure, forcing the water through the sealed portions of the pipes

If you’re looking for a leak, you should start by checking soldering portions. These are weaker spots along the pipe and are the most likely part to leak when there’s a clog. 

To unclog a clogged HVAC pipe, follow these steps: 

  1. Unplug your unit.
  2. Locate the leak. 
  3. If you can’t locate the leak, proceed. 
  4. Take the cap off the pipe. 
  5. Use a rag to wipe the face of the pipe.
  6. Run the machine and check for leaks.
  7. If leaking continues, proceed.
  8. Pour one cup of white vinegar into the pipe. 
  9. Let sit for 30 minutes to an hour. 
  10. Turn on the machine and check for leaks.
  11. The clog should be cleared. 

In a previous article, Can you snake an AC drain line? I discussed another method of unclogging your pipes. Check it out!

Read: Why HVAC Damper Keeps Getting Stuck Closed?

2. Replace a Broken or Cracked Drain Pipe

The drain pipe can become clogged with dirt, causing water to pool and leak out. Or, the pipe can become damaged or cracked from use or wear. 

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If this pipe is cracked, it can leak water into your home. However, you’ll also want to check where the drain pipe drips to ensure it’s not flooding or too close to your home. If water is pooling up near the foundation of your home, it can leak through the walls. 

I’ll discuss how to fix the water pooling outside your home in a moment. First, I’ll show you how to repair and replace a leaking drain pipe. 

Electrical or duct tape can temporarily fix a damaged or cracked pipe. But you’ll need to replace the pipe to fix the leak permanently. To replace your drain pipe, follow these steps: 

  1. Try to locate the leak.
  2. Unplug the unit.
  3. Use a saw to cut the pipe. 
  4. Use a drill to remove the remainder of the pipe from the wall. 
  5. Replace with a new pipe in the wall.
  6. Soder the drip pipe to the end. 
  7. Let it cool (1 hour at least).
  8. Test. 

This YouTuber gives a fantastic step-by-step guide for changing out a damaged drain pipe. Sections 3 through 6 are beneficial! 

There are several possible fixes if you notice a lot of water pooling around the drain pipe outside. The first is to use a large basin to collect the dripping water and repurpose it for your garden. 

You should call an expert if you want this pipe moved or redirected. This will require more knowledge about the unit’s internal workings and how to redirect moisture properly. 

Read: How To Tell If HVAC Zone Damper Is Normally Closed Or Normally Open? 

3. Replace a Damaged Condensation Collection Pan 

The condensation collection pan is essential for collecting water dripping below the unit. This pan can be challenging to locate, but checking your unit’s manual can help. 

This pan is usually a small pan located beneath the unit. If this drip pan overflows or leaks, it can cause severe damage to your AC unit. 

If you have a window unit, this will usually show as a streak of water dripping from the unit’s base. However, for industrial units, you’ll have to go outside and check the bottom of your unit. 

Rust is an obvious tell-tale sign of a damaged drip pan. Depending on the severity of the damage, you might be able to repair it yourself, or you might need an expert’s help. 

There should only be one drip pan beneath the evaporation coils for an outside unit. Attic units have two pans to protect the unit. To replace your own unit’s drip pan, follow these steps: 

  1. Identify your unit’s make. 
  2. Order or purchase a replacement drip pan. 
  3. Turn off the unit before working on it. 
  4. Use a screwdriver to remove the unit’s access panel.
  5. Find the evaporation coils to help you find the drip pan. 
  6. Unscrew or unlatch the drip pan. 
  7. Replace with a new drip pan.

Be careful when removing the old drip pan. They collect condensation from the coils, so there will probably be quite a lot of water in there. 

Read: Why HVAC Zone Damper Actuator Making A Clicking Noise? How To Troubleshoot?

4. Replace a Dirty or Broken Filter

According to the EPA, HVAC and heating unit filters are designed to remove air particles. This helps keep indoor environments fresh and clear of pollutants. 

However, if you fail to clean or change these filters consistently, it can cause your unit to overwork. Condensation will build up as the unit struggles to work correctly. 

Follow these steps to replace old or dirty AC filters: 

  1. Turn off your unit.
  2. Locate the air filter in an air duct or on a wall unit. 
  3. Remove the old filter. 
  4. Replace with a new filter. 

Home Depot rated replacing an old air filter as a beginner’s task. Although the job doesn’t require many tools or expertise, ensure you find the right size. If you get the wrong size, it can mess up the air filtration system.  

Read: Should An HVAC Zone Damper Bleed Air?

5. Replenish the Freon 

Freon is a chemical compound comprised of several different chemicals. These compounds include bromine, hydrogen, and chlorine. 

This compound creates an artificially cold environment by cooling pipes and moving air through them. Like placing a fan behind a bowl of ice, freon creates a cool atmosphere for your house’s air to pass through. 

If your AC unit is low on or runs out of freon, it can cause condensation to build up. If you notice your unit leaks, ensure it’s water and not freon. Since freon is naturally colorless and odorless, it emulates water in many ways. 

Signs that your AC unit is leaking freon include:

  • Your home is hotter than it should be
  • Your energy bill is higher than it should be

Never touch the liquid if you suspect it’s freon. If you suspect your unit is leaking freon, call an expert. 

Read: How Reliable Multi-Zone HVAC Systems Are?


HVAC units have a lot of different parts, which can be difficult to navigate. We hope this article helped give you some confidence for your next DIY project. 

Remember to never touch the liquid if you believe it could be freon. Sometimes units use a dyed variety of freon. If you see blue or green liquid, do not touch it. 

However, filters and regular maintenance are something you can do at home! If you find you need help, though, our team at HVAC Boss is here to help!