Boiling Water for Sanitation

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 to drink. Learn how to boil water for sanitation.

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 to a boil for a few minutes. Other types of pollutants, such as lead, are not so easily filtered out, however.

Before reaching a treatment plant, water from rivers and 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 212 F. In fact, if the temperature of the water is above 160 F, any organism in the water will not survive longer than 30 minutes.

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Boiling Water: How to Purify Water from Biological Contamination

To purify tap water:

  • Bring a pot to a rolling boil. 
  • Boil for at least one minute. 
  • Remove from heat and allow the water to cool before using it. 

It typically takes 30 minutes for the water to cool completely, so it is a good idea to plan ahead and boil more than you need in one sitting.

How Long Do You Have to Boil Water for It to Be Safe to Drink?

According to the Environmental Protection Agency (EPA), you must bring water to a boiling water temperature of 212 F and then keep it boiling for at least one full minute to kill bacteria, viruses, and other contaminants. At altitudes above 5,000 feet (1,000 meters), you should boil water for at least three minutes.

What to Do During a Boil Water Advisory

Boil water advisories are issued when there is a risk of biological contaminants in the water supply. Boil water advisory guidelines may include information about preparing food, drinks, or ice; dishwashing; and hygiene, such as brushing teeth and bathing. The usual advice is:

  • Use bottled water for drinking, preparing food, and cooking food.
  • If bottled water is not available, use boiled water.
  • Boil tap water even if it is filtered (for example, by a home water filter or a pitcher that filters water).
  • Do not use water from any appliance connected to your water line, such as ice or water from your refrigerator.
  • Breastfeeding is the safest infant feeding option. If you formula-feed your child, provide ready-to-use formula rather than mixing a powder with water.

During a boil water advisory, you should use bottled water or boiled water to:

  • Drink.
  • Brush your teeth.
  • Make coffee or tea.
  • Make ice.
  • Wash vegetables.
  • Cook pasta or vegetables.
  • Handwash dishes.

Why do you have to disinfect water during a boil water advisory?

According to the Centers for Disease Control and Prevention (CDC), if your local health officials issue a boil water advisory, it means that your community’s drinking water has, or could have, germs that can make you sick.

What Diseases Are Caused by Drinking Contaminated Water?

The CDC lists the top-five most common water-borne infections in the U.S. as:

Some of the most commonly reported side effects experienced from drinking contaminated water include:

  • Gastrointestinal problems.
  • Diarrhea.
  • Nausea.
  • Intestinal or stomach cramping.
  • Intestinal or stomach aches and pains.
  • Dehydration.
  • Death.

Editor's Note: This article was originally published on , and was last reviewed on .

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