Water pooling near an indoor air handler, or a sudden musty smell in a closet where the unit lives, is almost always traced back to one thing in South Florida homes: a clogged condensate drain line. It's one of the most common service calls we get from Cherry Hills, Aberdeen, and Canyon Lakes, and it has nothing to do with the refrigerant side of the system at all.
Here's the mechanism. As an AC unit runs, it pulls moisture out of the air and that water drips into a pan, then drains outside through a thin PVC line, usually run alongside the exterior of the house. In Florida's humidity, algae and mold grow inside that line constantly, and over months they build up into a slimy clog. Once the line backs up, the pan overflows, sometimes tripping a float switch that shuts the whole system down as a safety measure, and sometimes just quietly dripping into a ceiling or closet floor until someone notices a stain.
The fix itself is usually straightforward once the clog is found: a wet vacuum pulls the blockage out through the outdoor termination point, or in tougher cases a technician flushes the line and checks the pan and float switch for damage from standing water. What's less obvious is how often this gets missed during a routine tune-up that only checks refrigerant pressure and filter condition, because the drain line lives outside the cabinet and isn't always part of a quick inspection.
Companies that deal with humid coastal climates tend to list this as its own service rather than an add-on, which fits how often it comes up on its own without any other system problem. We treat it the same way on calls here in Boynton Beach: checking the condensate line and float switch as a standard part of any cooling complaint, not just when refrigerant or the compressor are suspected.
If your system has shut off unexpectedly or you've noticed moisture where there shouldn't be any, don't assume it's a major mechanical failure. Often it's a five-minute fix once someone actually looks at the drain line.