if it only happens when the car is cold (first start and until it warms up) it is condensation, and all cars do that ,,
the hot exhaust on to clod manifolds and pipe you may see drops of water coming out the exhaust tip
if this is what you are talking about , don't do anything except clean your exhaust every day, Oh! this happens mostly in the winter ,think about it , see cars with white smoke coming out on cars stopped at a red light with snow on the ground. jim