Distilled water is water that has many of its impurities removed through distillation. Distillation involves boiling the water and then condensing the steam into a clean container. Distilled water is also commonly used to top off lead acid batteries used in cars and trucks. The presence of other ions commonly found in tap water will cause a drastic reduction in an automobiles battery lifespan. Distilled water is preferable to tap water for use in automotive cooling systems. The minerals and ions typically found in tap water can be corrosive to internal engine components and can cause a more rapid depletion of the anti-corrosion additives found in most antifreeze formulations.