Why your HVAC is leaking water and what to do
Water near an HVAC unit comes from the condensate system or the coil. A clogged drain line or cracked drain pan lets condensation back up onto the floor. Ice forming on the coil, usually from low refrigerant or poor airflow, melts when the system shuts down and can spill more water than the drain handles.
Where does HVAC water actually come from?
Your HVAC system pulls warm, humid air across the evaporator coil.
That coil gets cold enough that moisture in the air condenses on its surface, the same way a cold glass sweats on a humid day. That condensation drips into a drain pan beneath the coil and then flows out through the condensate drain line. If the drain line clogs or the pan cracks, water has nowhere to go and backs up onto the floor. A refrigerant problem adds another path. Low refrigerant causes the coil to get too cold, and ice forms on its surface. When the system shuts off, that ice melts faster than the drain can handle, and water spills out. Every puddle you find near an HVAC unit traces back to one of those sources: the drain line, the drain pan, or the coil itself.
What can I fix myself when HVAC leaks water?
Start at the drain pan, the shallow tray that sits under the indoor coil.
If it is full, water is not draining. The condensate drain line runs from that pan to a floor drain or outside, and you can check it for visible blockages, a loose connection, or a section that has pulled apart. A slow line can often be cleared by flushing it with warm water from above the blockage. That is the extent of what you can do without risk. A coil that is frozen solid, a refrigerant line caked in ice, or water appearing from inside the air handler cabinet rather than from the drain are different problems. Anything involving ice points to either low airflow or a refrigerant issue, and refrigerant work is regulated and requires instruments you do not have.
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