That is basically condensation due to the car being cold,thats why typically you see less smoke and water when the car is warmed up,another note is thats why your mufflers have holes on the bottom side of the mufflers,to properly drain any accumilated h2o-water during the combustion process,also there is water buildup from low lying areas in the exhaust system which will dissipate when car reaches normal operating temerature.