Check your oil and see if its milky in color. This would defintly mean you have a blown head gasket. The water/coolant mixing with the oil will cause this to occur. Now you will have water come out the tailpipe due to condensation occasionally. But I'm not sure how much you are actually seeing. I personally have never seen that happen per say when one of my cars or friends have blown a head gasket. But I'm not saying that it wouldn't happen. My .02