Why is my mini-split leaking water?

Do this first

Turn the unit off at the breaker. Fujitsu’s manual lists water leaking from the unit as a reason to cut the power right away (Fujitsu).
Put a towel or a pan under it and move furniture out of the way.
Check the filters. Gree says a dirty filter can cut airflow, freeze the coil, and then leak as the ice melts (Gree). Wash them if they’re dirty. See the filters guide.
With the power off, shine a flashlight up through the louvers. If you see frost or ice on the coil, leave the unit off until it melts on its own. Don’t chip it or heat it. Keep the towels down; melting ice makes a lot of water. Not cooling or icing up covers why a coil ices.

Where the water comes out

These are common patterns, not a diagnosis:

Dripping from the bottom of the unit usually means the drain pan is full: the drain line is clogged, kinked, or sloped the wrong way.
Water running down the wall behind the unit can mean the drain connection behind the unit has slipped, or the unit isn’t level. Gree lists a unit that isn’t level as one cause of leaks (Gree).
Water spitting out with the air can mean the pan is full or the coil and wheel are coated with buildup.
Water dripping outside from a small tube is normal. That’s the drain doing its job.

Check the outside end of the drain

Follow the drain line, often inside the same cover as the refrigerant lines, to where it comes out. While the unit is cooling, it should drip. If the unit is leaking inside and nothing comes out outside, the line is blocked somewhere. Make sure the end isn’t buried in mulch, crushed, or full of mud or a wasp nest.

Don’t pour water into the indoor unit to flush the drain, and don’t push anything up the line. Fujitsu’s manual says not to expose the unit directly to water (Fujitsu). Carrier says a technician is the best fix for a clog. For routine drain-line care, Carrier suggests distilled white vinegar rather than bleach, in the drain line, not the unit (Carrier).

If your unit has a condensate pump

When a drain can’t run downhill to the outside, the installer adds a small pump, often in a box near the unit or inside the line cover. Gree lists a failed pump as one cause of indoor leaks (Gree). A pump runs on power, so it’s a service call, not a homeowner fix.

Error codes that point to the drain

Some units show a code when water backs up. On LG units, CH04 is a drainage problem (LG). On Gree cassette and ducted units, E9 means condensate overflow protection, and Gree says to call a licensed technician (Gree). Codes differ by brand and model. Error codes and blinking lights links each brand’s own list.

A water leak is not a refrigerant leak

Water from a mini-split is condensation from the air. A refrigerant leak doesn’t make puddles of water, and refrigerant products won’t fix a water leak.

Refrigerant does matter in one case: ice that keeps coming back after the filters are clean. Gree says low refrigerant needs a licensed technician to assess and recharge (Gree). EPA requires Section 608 certification to add or remove refrigerant from a mini-split, and asks homeowners to have leaks found and fixed rather than topped off (EPA).

Why New Orleans units make so much water

A mini-split pulls water out of the air as it cools. The more humid the air, the more water. NOAA’s normal dew point at the New Orleans airport is about 75°F in July and August (NOAA), so in summer the drain carries water almost all day. Over time, slime can build up in the pan and the line. EPA’s mold advice includes keeping AC drip pans clean and drain lines open (EPA). For what dew point means, see dew point in New Orleans.

EPA says wet materials dried within 24 to 48 hours usually won’t grow mold (EPA), so dry out any wet drywall or floor quickly. The mold guide covers what to do if it already has. For a central air system, see water around the indoor AC unit.