Hanging out with some volleyball friends, a guy asks me if it is bad to have water under his car.  He said that his water pump was just replaced.

To narrow down possibilties and find the root cause, I asked him if the color of the water was not clear and if he was running the air conditioner.  Sure enough, the water was clear and the air conditioner was on.

What he was seeing under his car is condensation from the air conditioner.  It is the result of the air conditioner cooling the air.

How Air Conditioning works