Water Filtration and Purification Basics

For my recent video in my bushcraft basics series I elected to make a short about water purification and filtration. It wasn’t the easiest video to research, but after a week of talking to experts and visiting outfitters, I came across the four best ways to filter and/or clean the water for drinking. Here is the short: https://www.youtube.com/watch?v=2LJlmuBglps Here is water you should never drink:

  1. Radioactive water
  2. Water near agricultural streams, because of pesticides
  3. Water downstream of a coal-ash treatment area
  4. Any water in a dump
  5. Water downstream of a gold mine
  6. Untreated water in just about any stream or lake

Filtering water is important to take out protists, bacteria and viruses. I talked to an expert at the WHO and he narrowed do the list to this:


  • Amoebiosis
  • Giardiasis – Fecal to oral (Giardia is the organism)
  • Crypto (resistant to chlorine disinfectants) (Cryptosporidium) the disease Cryptosporidiosis.

Bacterial (down to 200 nm)

  • Cholera (bacteria Vibrio cholerae) – most rapidly fatal (12-18 hours)
  • E. coli – Normal gut bacteria but certain strains produce toxins O157 causes blood in your kidneys. Toxiggelic and hemmoragic.
  • Typhoid : Caused by a type of Salmonella
  • Salmonella – bacteria that cause other diseases
  • Dysenteria (nickname for) – Chigella
  • Campilobactor – Often spread by birds and is in drinking water in streams

Viral (down to 25 nm)

  • Infectious hepatitis A / E
  • Rotavirus – globally main killer for infants
  • Norovirus – Transmitted through water

Many many others.

  • Ascaris worms – nutritional deficiencies
  • hookworms –
  • whipworms
  • Pathogenic helmins
  • Leptospira


Here are some of the things from my video if you want to get any for yourself:

If you want more info, I wrote this full article on Water Purification and Filtration Basics.

Written by Rob Nelson

Rob is an ecologist from the University of Hawaii. He is the co-creator and director of Untamed Science. His goal is to create videos and content that are entertaining, accurate, and educational. When he's not making science content, he races whitewater kayaks and works on Stone Age Man.

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