Water Leaking From Your AC? What It Means and What to Do

Water pooling around your indoor unit means the condensation your AC produces isn't going where it should. Every air conditioner pulls moisture out of the air as it cools — on a muggy South Sound afternoon, that can be gallons per day — and all of it is supposed to travel down a drain line and out of the house. When you see water instead, one of four things has gone wrong.

Why is my AC leaking water?

• A clogged condensate drain line. The most common cause by far. Algae, mold, and dust build up inside the drain line until water backs up into the pan and spills over. Our damp Pacific Northwest air keeps drain lines wet most of the year, which gives that biological gunk plenty of time to grow.
• A frozen coil that's thawing. If a dirty filter or low refrigerant iced the evaporator coil, the melt-off when the system shuts down can overwhelm the drain pan. The puddle is the second symptom — the ice was the first.
• A failed condensate pump. Systems in basements, garages, or closets often can't drain by gravity, so a small pump pushes the water out. When the pump or its float switch dies, water simply fills up and overflows.
• A cracked or rusted drain pan. Pans on older systems corrode through. Water then drips from the pan itself no matter how clear the drain line is.

What to shut off right now

1. Turn the system off at the thermostat. Every minute it runs, it makes more water.
2. If water is near electrical components, kill power at the breaker for the air handler or furnace too.
3. Soak up standing water with towels and put a shallow pan or bucket under the active drip.

If your air handler sits in the attic and you're seeing a ceiling stain below it, treat it as urgent. Drywall wicks water fast, and a sagging, saturated ceiling can fail suddenly. Shut the system down and don't wait a few days to see if it "sorts itself out" — it won't, and the repair bill shifts from HVAC to drywall, insulation, and paint.

What you can safely check

Look for a visible clog at the drain line's exit point outside (often a small PVC pipe near the outdoor unit) and clear any blockage you can reach. Check the filter — if it's filthy and the coil was frozen, replace it. Anything past that, including clearing the line with suction or a cleaning solution, opening the coil cabinet, or replacing a pump or pan, is a technician's job.

When to call a pro

If the leak returns after the system restarts, or you never found an obvious clog, book a diagnostic. A technician can flush and treat the drain line, test the float switch and pump, inspect the pan, and confirm the coil isn't freezing from a deeper airflow or refrigerant problem. Catching it at the "puddle" stage is far cheaper than catching it at the "ceiling repair" stage.