What to Do When There Is Water in Your HVAC Ductwork

Water in your home’s HVAC system ductwork is common after a major water event, such as external flooding, or household accidents, such as plumbing and appliance leaks. As a homeowner, your response depends on two things: the type of water that has entered the ductwork and where the ductwork is located in your home. As the owner of All Weather Heating and Air Conditioning, I’ve seen the consequences of delayed action, including reduced heating and cooling efficiency, hidden mold growth, and ongoing indoor air-quality problems. I’ve put together the following information to walk you through the process of identifying the type of water in your ductwork, deciding on the best remediation method, determining when to bring in a professional to complete a thorough ductwork inspection, and preventing additional damage in the interim.

Step 1: Identify the type of water in your ductwork
Water intrusion can be categorized by its contamination level, which drives the remediation approach. There are three main contamination types. In turn, each type of contamination requires a different response:

  1. Black water: Sewage-contaminated water.
  • Characteristics: Contains sewage and can pose serious health risks.
  • Immediate concern: High potential for pathogen exposure, structural contamination, and bacterial ingestion.
  1. Gray water: Lightly used water containing household cleaners, detergents, food products, and other non-sewage contaminants.
  • Characteristics: Contains household chemicals and organic matter. Gray water is less hazardous than black water, but it is still unsanitary and can potentially cause health issues.
  • Immediate concern: Structural contamination that requires thorough cleaning of the area and that must be cleaned and disinfected.
  1. Clear water: Non-contaminated water, such as rainwater, groundwater, or water from a clean supply line.
  • Characteristics: Contains little to no contaminants, but it can still affect equipment efficiency and home comfort if insulation or ductwork material is compromised.
  • Immediate concern: Potential loss of insulation effectiveness and comfort. The extent of the damage determines whether the material should be cleaned or replaced.

Step 2: Determine a remediation approach
Your approach will differ depending on whether the contamination water is black, gray, or clear, and whether the water is in metal ductwork, flexible ductwork, or insulation.

Black water remediation

  • Remove and dispose: Remove and discard all affected flexible ductwork and insulation inside and outside of the ductwork.
  • Clean and disinfect: You can often clean and disinfect the contaminated metal ductwork, but there are cases where replacement is necessary. Obtaining a professional ductwork inspection is the best way to determine when cleaning is sufficient and when replacement is required.
  • Add an indoor air-quality accessory: Consider installing a high-quality air purifier within the ducted system instead of using a portable table-top unit. A duct-mounted purifier can sanitize the entire ducted system and improve indoor air-quality throughout your home.
  • Hire a professional: Engage a professional HVAC team, such as the experienced technicians on the All-Weather Heating and Air Conditioning team, to perform a thorough ductwork inspection, recommend the appropriate remediation method, and then complete the remediation as well as ensure proper disposal of any contaminated materials.

Gray water remediation

  • Remove and dispose: Remove and discard all affected flexible ductwork and insulation inside and outside of the ductwork.
  • Clean and disinfect: Thoroughly clean and disinfect the contaminated metal ductwork, both inside and outside.
  • Add an indoor air-quality accessory: Consider installing a high-quality air purifier within the ducted system instead of using a portable table-top unit. A duct-mounted purifier can sanitize the entire ducted system and improve indoor air-quality throughout your home.

Clear water remediation

  • Remove and dispose: Consider replacing any exposed flexible ductwork and external insulation because the insulation’s R-value may be compromised, resulting in a loss of both heating and cooling efficiency and system capacity.
  • Clean and disinfect: If your system’s comfort and efficiency are still satisfactory you may opt to clean and disinfect exposed ductwork rather than replace it. A professional ductwork inspection will help you determine the best choice.
  • Add an indoor air-quality accessory: Consider installing a high-quality air purifier within the ducted system instead of using a portable table-top unit. A duct-mounted purifier can sanitize the entire ducted system and improve indoor air-quality throughout your home.

Step 3: Prevent additional damage

  • Drain water from ductwork in the crawlspace: Poke a small hole at the low point of the duct to allow water to drain. Direct the excess water into a bucket, onto the vapor barrier, or onto the ground after removing the vapor barrier.
  • Dry the ductwork: Set your thermostat fan to the On position to keep air moving. Continuous air movement helps dry out and dehumidify both the ductwork and the conditioned space.
  • Check ductwork periodically: Inspect your ductwork for any signs of lingering moisture, visible mold, or unusual odor. If you detect any of these, escalate to a professional evaluation.
  • Listen to your home comfort system: Activate your air delivery system from the thermostat. Walk around your entire home and listen to the sounds your home comfort system makes. If the sounds you hear are normal, there is no further action. If the sounds have changed from what you are accustomed to, there may still be water in the ductwork; you should turn your system off and continue to search for the duct(s) that have water infiltration.

Step 4: Address concerns about organic growth

  • Add an air purifier: If you suspect mold, bacteria, or long-term moisture exposure, an air purifier is a great helper. A product like the Reme Halo LED (or another HEPA-equivalent duct-mounted air purifier) can help mitigate microbial growth throughout the system.
  • Improve ventilation and humidity control: In addition to filtration, proper ventilation and humidity control are critical to prevent future organic growth. A professional assessment can provide a customized solution for your home.

Step 5: Obtain a professional ductwork inspection and customized remediation plan

  • Fully understand the extent of the contamination: A professional ductwork inspection will confirm the type of water in your ductwork as well as the scope of the contamination (flexible vs. metal, inside vs. outside sections). A ductwork from All Weather Heating and Air Conditioning will also evaluate the integrity and insulation value of duct materials and ensure there are no additional contributing factors, such as rodents or other crawlspace vermin.
  • Decide on the best remediation plan: The choice between replacing ducts or cleaning them hinges on contamination severity, insulation integrity, and the duct material. A well-trained technician evaluation helps you avoid unnecessary replacements and ensure safety. In addition, a professional can provide a clear, written plan with cost estimates and timelines.
  • Ensure your HVAC system operates safely and efficiently: Replacing or cleaning the wrong components can reduce system efficiency and comfort. A professional assessment ensures your system continues to operate at peak performance.
  • Provide a healthy indoor environment: A professional assessment will identify potential mold growth and air-quality impacts and recommend the best indoor air-quality accessories to alleviate persistent odors, coughing, allergy symptoms, or visible mold.

Finding water in your HVAC ductwork is more than a nuisance — it’s a signal that your indoor air quality and HVAC efficiency may be at risk. By identifying the water type, choosing the proper remediation, and engaging a professional to complete a comprehensive ductwork inspection, you can restore comfort, a healthy environment, and energy efficiency in your home. We invite you to call All Weather Heating and Air Conditioning to schedule a ductwork inspection or to assist with system maintenance, service, and equipment upgrades.