Why Is My AC Leaking Water? Causes and Fixes

A puddle next to your air handler or a water stain on the ceiling is one of the most common AC calls we get in South Florida. The good news: most leaks come from a handful of causes, and many are quick fixes if you catch them early.

Why your AC makes water in the first place

Your air conditioner doesn’t just cool the air — it pulls humidity out of it. That moisture condenses on the indoor (evaporator) coil, drips into a drain pan and flows out through a condensate drain line. In our climate, a typical system can remove several gallons of water a day. When anything in that path gets blocked or damaged, the water ends up on your floor instead.

1. A clogged condensate drain line

This is the number one cause by far. Warm, wet drain lines are perfect for algae and sludge, and over time they clog. When the line backs up, the drain pan overflows. If your system has a float (safety) switch, it may shut the AC off completely — which is why “the AC stopped and there’s water by the unit” usually points to the drain.

2. A rusted or cracked drain pan

Older metal drain pans rust through, and plastic pans can crack. Even with a clear drain line, a damaged pan leaks. This is common on systems 10–15 years old.

3. A frozen evaporator coil

If the coil freezes, the ice melts all at once when the system shuts off — more water than the pan can handle. A dirty air filter, blocked return vents or low refrigerant are the usual reasons a coil freezes. If you see ice on the copper lines, turn the system off and call for service.

4. A failed condensate pump

Some air handlers (often in closets or attics) use a small pump to push water out. If the pump fails, water backs up quickly.

5. A disconnected or poorly installed line

Lines can come loose, sag or be pitched the wrong way, especially after other work in the closet or attic.

What you can safely check yourself

• Turn the system off at the thermostat to stop more water from building up.
• Check your air filter. If it’s dirty, replace it.
• Look for ice on the copper refrigerant lines or the indoor unit.
• Find the drain line access (often a capped PVC “T” near the air handler). Many homeowners pour about a cup of distilled white vinegar into it every few months to slow algae growth.
• Dry the area to prevent water damage and mold.

If the water keeps coming back, the line is fully clogged, or you see ice, it’s time for a technician. A professional can clear the line with a wet vac or pressure, check the pan and float switch, and find out whether a refrigerant or airflow problem is behind it.

How to prevent leaks

Regular AC maintenance includes flushing and treating the drain line, checking the pan and testing the float switch — which prevents most leaks before they start. Changing your filter on schedule helps keep the coil from freezing.

Water near your air handler right now? Bentley HVAC’s repair team can usually get there the same day anywhere in Broward County.

Related: Leaks and dirty coils often show up together. Here’s what a dirty evaporator coil does to your AC.