Normal condensation vs. a real problem
Every air conditioner makes water — that's just the evaporator condensing humidity out of your air. A little moisture on the coil and a steady drip into the drain pan is exactly how the system is supposed to work. But when water drips from an actual supply vent, or you see a growing stain on the ceiling, something is wrong. The water is being pulled where it shouldn't go, and it's usually one of five specific causes.
A clogged condensate drain line
The condensate line carries water from the indoor coil to the outside. In Houston's humidity, algae and mold grow inside that white PVC pipe constantly. When it clogs, the drain pan fills and overflows — and gravity takes the water wherever it wants, often back through the ductwork and out a vent. Clearing the line and treating it to prevent regrowth usually solves it the same day.
Low refrigerant and a frozen coil
When the system is low on refrigerant, the evaporator coil gets too cold and ices over. When the ice melts, the water can overwhelm the drain pan and dribble out a vent. The real issue here isn't the water — it's the refrigerant leak that caused the ice. Adding refrigerant without finding the leak just kicks the problem down the road.
Damaged insulation or a rusted drain pan
A decade-old drain pan rusts through, and water leaks straight onto your ceiling. Likewise, if the suction line's insulation is torn, warm humid air condenses on the cold pipe and drips. Both are wear-and-tear items that are easy to spot on a service visit and cheap to fix before they become drywall damage.
When to call immediately
If the water is dripping from a vent directly over a finished ceiling, or the volume is more than an occasional drop, cut power to the AC and call. Every hour it runs while overflowing is another hour of water soaking into your ceiling. In Houston summers the system runs nearly nonstop, so a small leak becomes a big stain fast.
Frequently Asked Questions
Is it normal for my AC to drip water?
A small, steady drip from the unit's drain line is normal condensation. Water dripping from a supply vent or through the ceiling is not — it means a clogged drain, frozen coil, or a rusted pan.
Can a clogged drain line damage my house?
Yes. Overflow water soaks the ceiling, drywall, and insulation, and can trip the float switch that shuts your system off. It's worth fixing the same day in Houston's humidity.
Should I turn my AC off if vent is dripping?
If water is dripping from a vent, shut the system off to stop further overflow and call for service. Running it while overflowing only adds more water to the problem.
HVAC247PRO is a licensed Texas HVAC contractor (TACLB00105442E and TACLA95904E) serving the Houston metro 24/7. Call (346) 451-1559 or book an inspection online and a technician will be at your door the same day.