AC Water Leak in Florida

Every air conditioner produces condensate, which is simply water pulled from humid air as it passes over the cold evaporator coil. In Florida, where indoor humidity stays high for most of the year and systems run eight to ten months straight, a typical residential unit can produce several gallons of condensate per day during peak summer. Under normal conditions, this water collects in a drain pan and flows out through the condensate drain line to the outside of the home or into a plumbing drain.

An AC water leak starts when any part of that path breaks down. The single most common cause in Florida homes is a clogged condensate drain line. Warm, dark, constantly damp drain lines breed algae and slime that build up inside the narrow pipe until water can no longer pass. The pan fills, overflows, and water drips into the ceiling, walls, or flooring below. Homes in South Florida and Central Florida, where cooling season is longest, see this most often.

Other frequent causes include a cracked or rusted drain pan, especially in older air handlers where metal pans corrode. A frozen evaporator coil is another culprit: when airflow is restricted by a dirty filter or low refrigerant, the coil ices over, then releases a sudden rush of meltwater that overwhelms the pan. Improper installation matters too. If the air handler or the drain line was not installed with the correct slope, water sits in the line, accelerating clogs. In Florida attics, where many air handlers are located, installers sometimes run long horizontal drain lines that are especially prone to sagging and blockages.

A float switch, also called a condensate overflow switch, is a small safety device designed to shut the AC off when the drain pan fills too high. Many Florida homes have one, and it is required by current building code for attic installations, but older systems often lack it. Without a float switch, an overflowing pan can leak for days or weeks while the homeowner is away, which is exactly how small AC leaks turn into major water damage restoration projects.

1. Turn the AC off at the thermostat. Stopping the system stops new condensate from forming. Switch the thermostat to off, not just to a higher temperature.
2. Shut off power if water is near electrical parts. If water is dripping onto the air handler's electrical compartment, the breaker panel, or any outlets, turn off the breaker for the air handler before touching anything wet. If you are unsure, call for help instead of guessing.
3. Contain the water. Place towels, buckets, or a wet vacuum under the drip. Move furniture, electronics, and valuables away from the wet area. If a ceiling is bulging with trapped water, do not poke it, since a sudden release can flood the room.
4. Check the condensate drain line outside. Find where the line exits the house, usually a PVC pipe near the outdoor unit or on an exterior wall. If it is barely dripping while the system was running, it is likely clogged. You can try clearing it with a wet/dry vacuum on the outside end, which often pulls the clog out.
5. Look at the drain pan. If you can safely access the air handler, check whether the pan is full, cracked, or rusted through. Do not attempt electrical repairs yourself.
6. Document the damage. Take photos of stains, puddles, and any damaged belongings before cleanup. Good documentation helps with insurance documentation if you file a claim.
7. Start drying. Mop up standing water, run fans, and if you have one, run a dehumidifier. In Florida humidity, wet drywall can start growing mold within 24 to 48 hours, so drying quickly matters. For soaked ceilings, walls, or flooring, consider professional water extraction and structural drying.

If water has reached drywall, insulation, or subflooring, surface drying is not enough. Moisture trapped inside building materials keeps feeding mold long after the visible puddle is gone. A moisture meter reading by a restoration professional can tell you whether the structure is actually dry. See our emergency water damage checklist for a printable version of these steps.

• Flush the condensate line every few months. Pouring a cup of white vinegar or a dedicated drain-line treatment through the line's access tee helps prevent the algae and slime buildup that causes most clogs. Avoid harsh chemical drain cleaners, which can damage PVC and pans.
• Change or clean the air filter on schedule. A clogged filter restricts airflow, which can freeze the evaporator coil and trigger a sudden overflow. In Florida, check filters monthly during cooling season.
• Install a float switch if you do not have one. This inexpensive safety device shuts the system down before the pan can overflow. It is one of the highest-value upgrades for attic air handlers.
• Schedule annual professional maintenance. A technician can check refrigerant levels, clean the coil and pan, verify drain slope, and catch corrosion before the pan fails.
• Keep the area around the air handler clear. Stored items in closets or attics can knock drain lines loose or hide early drips. Leave the unit accessible for inspection.
• Consider a secondary drain pan. For attic installations, a larger secondary pan under the entire unit catches overflow from a failed primary pan and routes it to a visible location.

If your system is more than 12 to 15 years old, ask your HVAC technician about the drain pan and coils at the next service visit. Corrosion failures cluster in older equipment, and proactive replacement is far cheaper than ceiling repair. For broader guidance, see water damage help and our emergency response guide.

Common Questions