Safety Why Does Boiling Water Make It Safe to Drink? By UPMC, February 3, 2017 Turning on the tap for a glass of water is a convenience we often take for granted — until we can no longer do so safely. When a city instates a “boil water advisory” it means the tap water may no longer be safe or sanitary to drink. RELATED: How to Prevent Recreational Water Illness How Does Boiling Water Make It Safe to Drink? Boiling water makes it safe to drink in the event of some type of biological contamination. You can kill off bacteria and other organisms in a batch of water simply by bringing it a boil. Other types of pollutants, such as lead, are not so easily filtered out, however. Before reaching a treatment plant, water from rivers and/or reservoirs contains a variety of organisms, such as bacteria and viruses. Even though the water might appear clean, it is most likely home to unsafe microorganisms. Some types of bacteria are harmful to consume, and can cause digestive problems along with symptoms of cramping and diarrhea. Boiling water is the most efficient method of purification when a person does not have access to safe, treated water. Many organisms cannot survive when water reaches its boiling point of 212o Fahrenheit. In fact, if the temperature of the water is above 160o Fahrenheit, any organism in the water will not survive longer than thirty minutes. RELATED: Avoid Scalding Burns in the Household Boiling Water: How to Purify Water from Biological Contamination To purify tap water: 1. Bring a pot to a rolling boil (212 o F) 2. Wait approximately one minute 3. Then reduce the heat and allow the water to cool before using it to drink, cook, or brush your teeth It typically takes thirty minutes for the water to completely cool, so it is a good idea to plan ahead and boil more than you need in one sitting. Make sure to use the boiled water for tasks such as washing fruits and vegetables or hand-washing dishes.