Replace the water every six months. While the storage of water is fairly simple and straight forward, water purification is a bit more complex. In addition to having a bad odor and taste, contaminated water can contain microorganisms that cause diseases such as dysentery, typhoid and hepatitis. You should purify all water of uncertain purity before using it for drinking, food preparation or hygiene. There are many ways to purify water.
None is perfect.
Often the best method is a combination of methods. Boiling and disinfecting will kill most microbes but will not remove other contaminants such as heavy metals, salts and most other chemicals. Distillation will remove microbes that resist boiling and disinfecting plus heavy metals, salts and most other chemicals. Before purifying, let any suspended particles settle to the bottom, or strain them through layers of paper towel or a clean cloth. Purification - Boiling Boiling is the safest method of purifying water.