you're problem most likely is the a/c drain tube. usually it will get clogged and what we do at our shop is pull it off the bottom of the evap. box and blow it out with shop air. its not hard to find. sorry i dont have picx. but just look where the evap box is and there is a rubber tube that leads down. pull it off the box, blow it out, then put it back on. only takes a minute. you might have to pull the carpet back. im not sure never looked on my car. but that sounds like the case for you if you had your a/c on and no water under the car - means the drain tube is clogged. try it out!