Water leaking from a split AC's indoor unit is one of the more common service calls, and while it can look alarming, the cause is usually mechanical rather than electrical. The condensate drain line, which carries away the water naturally produced as the unit dehumidifies room air, can become blocked by algae or dust buildup over time, causing water to back up and overflow the drain pan instead of draining outside as intended.
An indoor unit installed without the correct slight backward tilt won't let condensate flow toward the drain outlet properly, leading to a slow but persistent drip even with a completely clear drain line. A clogged or dirty air filter can cause the evaporator coil to ice up during operation; when the unit is turned off or the ice naturally melts, the resulting meltwater can exceed what the drain pan and line are designed to handle at once.
Low refrigerant can similarly cause coil icing through a different mechanism, again leading to a leak once the ice melts. Because several distinct issues produce the same visible symptom, a technician typically checks the drain line, unit tilt, filter condition, and refrigerant level in sequence rather than assuming any single cause.