First, understand that your air conditioner is a great big whole-house dehumidifier where the primary function is to remove, or pull moisture from the humid air (what makes you uncomfortable) in your home.
Here's the 'normal' function of your air conditioner, the way it's designed to work:
We mainly count on our air conditioners to cool the air in our homes, but they also perform another function: dehumidification. When your air conditioner is running, the evaporator coil gets extremely cold. As warm air from your home is blown over the coil, the air cools down and releases moisture (thereby dehumidifying your air).
Your AC’s inside unit contains the evaporator coil that cools the warm air blown over it. This causes condensation to form on the coil. Everyone has seen water droplets form on a cold glass of water or cold pop can on a hot day.
The moisture on the evaporator coil drips into a drain pan and then it runs down a condensate drain line (a white PVC pipe) that leads to a floor drain or exits out your home
This is a GOOD thing, and a sign that your system is doing its job. But, there's a difference between water draining and water leaking.
So Here's A Common Problem For A Neglected Air Conditioning System
Water leaks in central air conditioners are almost always caused by a problem with the condensate pan or drain pipes. A clogged condensate drain line is the most common cause of water leaking from your AC into your home.
When your drain line gets clogged with dust, dirt, or mold, water backs up in your drain pan. With nowhere to go, that water will begin to spill over your drain pan and onto your furnace or air handler and then onto your floor.
You’ll need to unclog it. There are multiple unclogging methods, you can try a rigid wire to poke up the line or better yet, use a wet/dry vac on the condensate line.
But the surefire way is to have a professional use a special vacuum to suck the stuff that's blocking the line out. Also, a pretty good argument to schedule a tune up.