Does Boiling Water Really Purify It?

March 6, 2018

Water is sourced from all different locations: faucet, bottle, stream, pond, cloud. It’s a renewable resource and vital to human survival. We use it to bathe, cleanse and nourish, among other things. Ironically, if the water used to survive is impure, the result is the exact opposite of human survival. Drinking water that has not been treated for disease-causing organisms can be fatal.

A quick and safe way to ensure pure water is to boil it. However, this is not a catchall for clean water, and there are a few questions to address before signing boiled water off as safe.

Does Boiling Water Really Purify It?

In short, yes.

Boiling water inactivates waterborne pathogens by using heat to damage the structural components and disrupt their essential life process. The heated water pasteurizes the liquid, which kills all organisms present that are harmful to humans.

What is removed?

Common pathogens found in contaminated drinking water are protozoa, bacteria or virus. Human digestion any of these microorganisms can cause illness, or even death. These disease-causing organisms include:

  • Giardia
  • Cryptosporidium
  • Endameba
  • Eggs of worms
  • Vibrio cholera
  • Shigella
  • Salmonella
  • Strands of E. coli, Hepatitis A and rotaviruses

Is anything left behind?

Pasteurization: kills organisms that can cause harm to humans.

Sterilization: kills all organisms present.

Since boiling only pasteurizes the water, some bacterial spores not associated with waterborne disease do survive. These spores, such as clostridium and bacillus, are not harmful to humans.

More importantly, boiling water does not purify water that is contaminated with chemicals, raw sewage or dirt and minerals. The particulate matter within this water impairs the effectiveness of boiling. Cloudy water is full of debris and causes digestive issues. Filter the water before boiling it.

How does the boiling process work?

Effectiveness is directly related to temperature and time. Water should be brought to 212 degrees and kept at a rolling boil for one minute in order for it to purify, according to the United States Environmental Protection Agency. Afterward, it should be covered and cooled at room temperature.

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Jonathan Myers

We're very glad we got this installed. The technician, Alberto, was very polite and thoroughly explained what he was doing and what we would need to do.

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Alberto kept me informed on his arrival time. He was professional and exceeded my expectations concerning the install of the water filtration system. I also need to put a plug in for Tracy for her patience and skills at making things happen behind the scenes...a true unsung hero. They both deserve a raise!


I just had my system installed by Alberto and Jay, and I wanted to say that they rocked. Got it all in and gave me some instructions to follow, all while being determined to detail and professional. Thanks, fellas.