[bongodongobob]

That's not normal, your AC is broken or has a plug in the drain if it's a window mount unit.

If it's central air, you're just mistaken.

[MisterTea]

Sigh. The water condenses on cooler surfaces INSIDE the AC unit and drains outside. This is why mold grows on the squirrel cage and the walls of the blower housing. Even happens on wall mounted split units.