How to Fix a Clogged AC Drain Line

Posted On: April 6, 2021

As indoor air circulates through your air conditioner’s evaporator coil, dust, dirt, and other airborne particles can be trapped by moisture. Buildup of this debris can be carried off as condensate drains from the coil. Over time, it can become trapped in your condensate drain line, causing blockage. As a preventive measure, many HVAC technicians will inspect and clear debris from the AC condensate drain during your annual maintenance tune-up. If this service isn’t done regularly, you could potentially experience a clogging issue.

Signs Your AC Drain Line Is Clogged

A clogged AC drain line symptoms include:

  • Musty, moldy smell near your indoor unit or in air from the registers/vents
  • Standing water near the indoor unit
  • Water damage in areas near the indoor unit
  • AC system is not cooling your home
  • AC system shuts down or doesn’t turn on

If you experience any of the above situations, it’s probably time to contact Short Pump Heating & Air so we can schedule a visit and clear the clogged air conditioner drain line.

Here’s what to expect when your SPHA technician arrives.

STEP 1 – Power Off the Air Conditioning Unit: The technician will likely turn the system’s power off, even if it is not running at the time. This is for the safety of the technician as well as to protect the HVAC system from additional condensate-related damage.

STEP 2 – Check the Drain Pan: One of the first things the technician will do is locate the drain pain and check for standing water. If standing water is present, it can either be soaked up with rags or removed with a wet vac. The dry condensate pan should be thoroughly cleaned to help prevent the growth of mold.

STEP 3 – Unclog the Drain Line: After physically removing any visible debris from the AC drain or drain pipe opening, most likely the technician will clear the clogged drain by using high-pressure air blown through the lines. They might also test that the line is clear by pouring clean water through the drain and observing its ability to flow out.

STEP 4 – Finish Up: Once the drain has been cleaned and tested, your technician will reassemble or reinstall any parts removed, restore power to the system, and check to be sure everything is functioning properly.


If you have a situation with a clogged air conditioner drain line and you have exhausted the troubleshooting steps outlined previously, call Short Pump Heating & Air at 804-364-9040 so we can set up a service visit and properly diagnose the issue. 

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