Liquid dripping out of a car's tailpipe can be either normal or serious, and those who are concerned should gather some of the liquid and try to identify it; if the liquid is water, then this is part of a normal process of moisture condensation within the combustion chamber and exhaust system. Water vapor is naturally created as a result of the combustion that takes place within a car's engine, and when temperature conditions are right, the water vapor will condense into drops rather than evaporating. Those who are unsure if the liquid coming out of their car's tailpipe is actually water may want to take their vehicle to a reputable mechanic to have the issue diagnosed.
One way to test the liquid that comes out of a car's exhaust pipe is to observe its color. If it has a clear color, it can reasonably be assumed to be water. However, the water that condenses may collect dirt and other particles and take on a different color, so this is not necessarily a foolproof test. Smell is another technique that can be used to determine the identity of a liquid that is coming out of a car's tailpipe. Sweet-smelling liquid may indicate a more serious problem with the engine.