How to Get Water Out of Air Ducts - AC Duct Water Damage

Our AC units are handling moisture on a daily basis. The ducts of these AC units play an important role in regulating air quality in your rooms.

One of the ways they do this is through ventilation and controlling humidity levels in your home.

If you’ve read our blog before, you’d know the importance of regulating your indoor humidity. When it’s optimal, you’ll enjoy a comfortable, pathogen-free life. 

This is all great, until it’s not.

AC ducts are prone to water leaks and damage and if not properly repaired, they’ll just continue to deteriorate and cause you problems, one of which is mold in your AC unit.

Let’s avoid this. Today you’ll learn what exactly leads to water damage in AC ducts, why you should repair it right away, and how to do so with ease. 

Here we go!

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How Your AC Ducts Handle Moisture

Ducts play a fundamental role in the functionality of air conditioning units, acting as conduits for air circulation. One of the primary purposes of ducts is to help distribute warm and cool air evenly throughout your house.

You see, when air circulates, ducts serve as channels for air to return to the central AC unit. This “return air” contains heat and moisture that must be handled before being recirculated.

This wet, warm air passes through the coils in the AC unit, where moisture and heat are extracted. The moisture then condenses on the surface of this coil.

As the moisture condenses, it forms water droplets. These droplets then drip down into a shallow tray known as the drip pan, which is positioned beneath the coil. Connected to the drip pan is a condensate drain line, which allows the water to be directed away from the AC unit.

So, why are we telling you all of this?

Well, you should first know how moisture is handled throughout the AC unit and ducts. This will help you better understand why there has been a leak and then how to properly mitigate it.

Why is There Water in My AC Ducts

As we’ve said, the condensed water from the AC is typically collected in a drip pan beneath the coil and directed out of the system through a condensate drain line. If this drain line is clogged or damaged, the water can leak into the ducts.

Another possibility is that there might be a leak in the ductwork itself. Ducts can develop holes, gaps, or disconnections over time. In some cases, inadequate insulation on the ducts could also lead to condensation forming on their outer surfaces.

This can all result in water damage in your AC ducts.

Consider the humidity levels in your living space. If the humidity is exceptionally high, dehumidification might be more pronounced, and if the drainage system is not functioning properly.

So, in summary, if your drip pan or drainage line are damaged or just not working properly (this could also be due to improper installation), this can lead to water damage. The ductwork itself may also have cracks or loose connections.

Can Water in Ducts Come from Elsewhere?

Yes, in more rare instances, you can have water damage from a completely different source. 

Remember, the ductwork is a conduit allowing for air to pass through the house nicely. There are plenty of things surrounding your ducts that could get damaged, have the water leak through them, and then reach your air ducts.

One of the more common sources is roofing leaks. If your roof has any openings or damaged areas, especially during heavy rainfall, water can seep through and find its way to the ducts.

Similarly, plumbing near the ductwork can lead to water damage if the pipes leak (for instance, leaks from bathroom plumbing next to ducts).

Condensation from HVAC components other than the main AC unit can also be a factor. 

Again, while the coil in the AC unit is a primary source of condensation, other components like supply ducts passing through humid spaces, such as crawl spaces, can accumulate condensation too.

Issues related to humidifiers within the HVAC system can also lead to excess moisture.

Gutters can be responsible too. If gutters are clogged or damaged, rainwater may overflow and run down the walls, potentially entering the ductwork through openings or seams.

Lastly, if your AC unit is in the basement, a condensate pump is likely used to pump the collected water upward. This pump can get damaged through cavitation.

Why is AC Duct Water Damage Bad

Well, if not for the water itself that shouldn’t be there, many more issues can pop up because of AC ductwork water damage:

  • AC unit malfunctioning
  • The ductwork itself will deteriorate, providing poor indoor air quality and ultimately requiring an expensive replacement
  • And mold and mildew

The last one is a particular concern. Mold in your AC means improper air circulation, or no circulation at all, and a plethora of mold spores to be inhaled by everyone in your house.

Mold can trigger allergic reactions and asthma in those prone to that, and will continue spreading and eating up most of the stuff that comes in its way. 

So, mold can grow in my ductwork?

The answer is yes. Here’s how that happens:

  • Mold needs moisture to grow, and when there is water in the AC duct, that’s the ideal environment
  • Mold also needs nutrients; dust, dirt, and even pet dander (tiny, even microscopic, flecks of skin shed by cats, dogs, and other animals with fur or feathers) present in the ducts can do it
  • Airborne residues from our cooking can reach the ducts, providing even more nutrients
  • The insulation lining the ducts, if it becomes wet or damp and has mold, can also be eaten up
  • Inadequate ventilation within the duct system can contribute to the stagnation of wet air, allowing for moisture to accumulate

Okay, got it. What do I do?

We’ll now get to the steps of removing water out of your AC ducts and making sure it doesn’t happen again.

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As soon as you call the number below, you’ll be connected with a professional restoration company in your area. Free, with no advertising or commitment.

How to Repair AC Duct Water Damage

Before we begin:

  1. Materials Needed:
    • Mastic sealant or duct tape
    • Wet-dry vacuum or pipe cleaner
    • Mild detergent or water-vinegar solution
    • Antimicrobial solution
    • Insulation materials (if replacement is required)
    • Dehumidifiers
    • Protective gear (gloves, mask, goggles)
  2. Time Estimate:
    • The repair time depends on the extent of damage but it may range from a few hours to a day (including drying time)

Got it? Let’s now get into the steps.

  1. Identify and Fix Source of Water: Begin by inspecting the ductwork for visible leaks. Focus on joints, seams, and connections. Seal any visible leaks using mastic sealant or appropriate duct tape designed for HVAC use. Ensure a secure and airtight seal to prevent future leaks. Now, if the source of the damage comes from something else, like a roof or plumbing, then you have to repair that before you proceed.
  2. Clear Blocked Drain Lines: Check the condensate drain line for blockages. Use a wet-dry vacuum or a pipe cleaner to clear any debris or clogs.
  3. Replace Damaged Insulation: Inspect the insulation around the ducts for damage or dampness. If its compromised, replace it with the new insulation we’ve told you to get your hands on.
  4. Clean and Disinfect: Clean the affected areas of the ductwork using a mild detergent or a water-vinegar solution. Wipe down surfaces to remove contaminants and debris. After cleaning, apply an antimicrobial solution to disinfect the area.
  5. Use Drying Equipment: Use dehumidifiers to dry out the area. Dehumidifiers are large devices great for sucking out moisture from big, damp materials like drywall, insulation, and carpets. They’ll be really handy if the damage has spread deep into and beyond your ducts.

When to Call a Professional:

  • If water damage is extensive or difficult to address
  • If there is a lot of mold that you can’t seem to handle yourself
  • If the source of water is challenging to identify
  • If you can’t repair the AC or ducts themselves

Now, which type of professional should you call?

When it comes to repairing the actual water damage itself and removing the subsequent mold, you should call a company specializing in restoration services. 

So if you can’t do the five steps we’ve outlined, call a restoration company.

However, if you’re struggling to repair the AC or the ducts themselves, call an AC contractor.

There are a number of issues you may not be able to get over:

  1. Hidden Ducts or Hard-to-Reach Areas: If portions of the ductwork are inaccessible or hidden behind walls, ceilings, or other places.
  2. Extensive System Design or Zoning Problems: Complex duct systems with intricate designs, multiple branches, or zoning configurations may pose challenges when trying to ensure proper airflow and temperature control.
  3. Custom Ductwork or Unusual Materials: Some buildings may have custom ductwork designs or use non-standard materials you may not understand or know how to work with (like, for example, ducts with an acoustic design).
  4. Airflow Balancing Issues: Balancing the airflow in a duct system to ensure consistent temperatures throughout the building can be complex, like adjusting dampers and addressing imbalances.
  5. Commercial Duct Systems: Duct systems in large commercial or industrial buildings can be extensive and intricate. Addressing issues in these settings may involve dealing with large-scale equipment, advanced control systems, and unique challenges specific to these HVAC systems.
  6. Integration with Other Building Systems: In some cases, the damaged ductwork is intricately integrated with other systems, such as fire suppression, security, or environmental control systems. 
  7. Advanced HVAC Technologies: Duct systems associated with advanced HVAC technologies, such as variable refrigerant flow (VRF) systems or high-efficiency heat recovery systems, that got damaged.

If enough of it is present, water can make dealing with any of these very, very challenging. This is when things get really complex and multiple parties may be involved.

And then there are instances where mold may have grown so much that you’ll need a new unit. The unit replacement is what AC professionals will help you with, while restoration guys remove mold. 


There you go. Hopefully, we haven’t overwhelmed you too much. 

The tips we’ve outlined will help you mitigate water damage from your AC ducts and ensure it doesn’t happen again. Just make sure to conduct more regular maintenance.

Also, if things got out of hand, use RepairSprout to find a restoration professional near you!

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