Refresh Demineralised Water 5L Ultra Pure Steam Distilled Water - S2190PET Pure water has many commercial applications where a very high level of water purity is required. Such commercial applications include laboratory and scientific applications, laser cutting equipment etc. Pure water is also commonly used to top up lead acid batteries used in cars and trucks. The presence of other ions commonly found in tap water will cause a drastic reduction in the battery’s lifespan. Pure 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. Using pure water in steam irons for pressing clothes can help reduce mineral build-up and make the iron last longer.