What are the signs of a clogged AC condensate drain line?

Recognizing that your air conditioning condensate drain line is clogged involves observing specific water damage warning signs and safety system shutdowns. Key indicators include water pooling or puddling directly around the base of your indoor air handler or leaking from a mini-split wall cassette, a musty mold odor lingering in your room, or active water leaks dripping from ceilings. Additionally, modern HVAC systems feature safety float switches that automatically cut power to your entire air conditioning system to prevent a flood when primary lines clog. You can troubleshoot by inspecting the drain pipe termination point outside. You can verify that your line is clogged when clearing the blockage with compressed air or a shop vacuum restores normal drainage and stops all indoor overflows.