AC Leaking Water Inside the House: Causes and Fixes

In Southwest Florida, your AC does two jobs: it cools the air and pulls water out of it. On a humid summer day, that can mean gallons of water draining from your system. When that water can't drain, it ends up on your ceiling, in a closet or on the floor. If you can't find where the water is coming from, our leak detection in Naples can trace it and dry the damage.

Why does an AC make water in the first place?

Warm, humid air passes over the cold evaporator coil inside your air handler. Water condenses on the coil, the same way water forms on a cold glass. That water drips into a drain pan and flows out through a condensate drain line, usually a white PVC pipe that ends outside or in a drain. In Naples, with high humidity much of the year, that line works hard.

What are the most common causes of an AC leak?

Clogs are by far the most common. Algae, dust and slime grow in the line, especially in warm climates like ours.

What can you check yourself?

1. Turn off the AC.This stops new water from forming while you look.
2. Check the drain pan.If it's full, carefully remove water with a wet vac or towels.
3. Find the drain line outlet.It's often a PVC pipe outside near the condenser.
4. Clear the line.A wet/dry vac held to the outdoor end can pull out many clogs.
5. Change the air filter.A dirty filter can freeze the coil and cause leaks later.
6. Check for ice.If you see ice on the lines or coil, leave the AC off and call an HVAC tech.

Many HVAC technicians suggest flushing the line with a cup of distilled vinegar every few months to slow algae growth. Check your system's manual first.

Where does AC water damage show up?

• Brown rings on ceilings below an attic air handler.
• Wet carpet or baseboards near an AC closet.
• Bubbling paint or soft drywall on walls next to the unit.
• A musty smell when the AC turns on.
• In condos, water showing up in the unit below.

Water from an AC leak can soak into drywall and insulation for days before you see it. Our guide to the signs of water damage in walls shows what to look for.

How do you prevent AC leaks in a Naples home?

• Have your AC serviced at least once a year, ideally before summer.
• Change filters every one to three months.
• Flush the condensate line regularly.
• Ask your HVAC tech about a float switch that shuts off the AC if the pan fills.
• Check the AC closet or attic platform for water every few weeks.

When should you call a professional?

Call an HVAC technician when the line won't clear, the pan is cracked, the coil is frozen, or the pump or float switch has failed. Call a water damage pro when the leak has wet a ceiling, wall, carpet or the unit below. Wet ceiling drywall can sag and fall, and moisture inside walls can grow mold within days. For ceilings, see how to repair a water-damaged ceiling.

What to do if the AC leak reached your ceiling

If water has soaked the ceiling below an attic unit, put a bucket under the drip and poke a small hole at the lowest point of a bulge to let water drain in a controlled way. This keeps the whole panel from falling. Turn off the AC and the power to any light fixture in the wet area. Then call for drying, so the ceiling and the insulation above don't grow mold.