Distilled water is water that has been boiled into steam and then condensed back into liquid form, removing impurities and minerals. This process makes it one of the purest forms of water. Unlike tap water, which contains minerals and may have been treated with chlorine and fluoride, distilled water is free from these substances. It is often used in situations where purity is crucial, such as in medical settings, laboratories, and for certain household tasks like ironing. However, because it lacks minerals like calcium and magnesium, it may taste flat and is not ideal for drinking as the sole source of hydration. Some people use distilled water for cooking, but it's important to note that it doesn't provide the minerals that regular tap water does. If you use it in a fish tank, you'll need to add a sea minerals supplement. Distilled water can also be used in appliances to prevent mineral buildup. Unopened bottled distilled water can last indefinitely if stored properly.