This is the “usual suspect.” Your air conditioner’s job is to remove heat and moisture from the air. That moisture collects on the evaporator coil and drips into a drain line that leads outside.

• • The Problem: Over time, algae, mold, and dust can create a thick “sludge” that blocks the pipe.

  • The Fix: If you’re handy, you can use a wet/dry vac on the outdoor end of the line to pull the clog through. However, a professional high-pressure flush is the only way to ensure it’s completely clear.

Directly underneath your indoor evaporator coil sits a drain pan.

• • The Problem: In older units, metal pans can rust through, while plastic pans can crack. If your air conditioner leaking water is an older model, the pan has likely reached its expiration date.

  • The Fix: The pan will need to be replaced. This is a job for a technician, as it often requires navigating tight spaces within your HVAC cabinet.

If you see ice on the copper lines leading to your AC, or if the unit is dripping heavily while it “thaws out,” you have a frozen coil.

• • The Problem: This is usually caused by restricted airflow (a very dirty filter) or low refrigerant levels. When the ice melts, it produces more water than the drain system can handle.

  • The Fix: Turn the AC off and switch the fan to “On” to melt the ice. Change your air filter immediately and call a professional to check your refrigerant levels.

Does your AC live in a basement where the water has to be pumped up to reach a floor drain or the outdoors?

• • The Problem: You likely have a condensate pump. If the motor fails or the float gets stuck, the pump reservoir will overflow onto your floor.

  • The Fix: Check the power to the pump. If it’s plugged in but not pumping, it likely needs a replacement motor.

Sometimes, the simplest explanation is the right one.

• • The Problem: Due to vibrations or accidental bumps, the PVC pipe that makes up your drain line can actually vibrate loose from the unit.

  • The Fix: Inspect the white PVC piping connected to your indoor unit. If it’s wobbly or disconnected, it may simply need to be re-fitted and glued back into place.

On those rare, extra-humid Calgary days, your AC has to work overtime.

• • The Problem: If your ductwork isn’t properly insulated, the cold air inside the ducts can cause “sweat” (condensation) to form on the outside of the metal. This moisture then drips through your ceiling or onto your floor.

  • The Fix: A professional can ensure your ducts are wrapped and sealed properly to prevent this “sweating” effect.