Does Berkey water filter remove Giardia and Cryptosporidium?

Cryptosporidium and Giardia

Giardia and Cryptosporidium have emerged as waterborne pathogens of concern for public health. Giardiasis and cryptosporidiosis are intestinal infections caused by the protozoan parasites giardia lamblia and cryptosporidium parvum. 

Cryptosporidium is a parasitic protozoan having a complicated life cycle. At some stage of its life, it exists alongside the cells that line the intestines of animals and humans. While in the human or animal host, cryptosporidium produces an oocyst, which then forms a dormant protective cyst in the intestines.

The cyst is a microscopic particle that can easily be carried by water. The oocyst is discharged from the host to the environment in feces. Giardia also form protective cysts that allow the parasite to survive in the environment until ingested by a host.

Many but not all available home water filters remove Giardia and Cryptosporidium. Does Berkey water filter remove them?  Short answer:  Yes, the Berkey water filters filter out both contaminants from the water.

The Environmental Protection Agency’s minimum removal standard for cryptosporidium is 99%, or a 2-log reduction. Black Berkey Filters remove cryptosporidium to greater than 99.996% (log 4.6). That is over twice the EPA standard, by log 2.6.

For Giardia lamblia, the EPA minimum removal standard is 99.9%, a 3-log reduction. Black Berkey filters have been tested to reduce Giardia cysts by greater than 99.994%, or log 4.6. This also exceeds the EPA standard.

Diarrheal disease is a leading cause of mortality and morbidity worldwide for children under 5 years of age and Cryptosporidium parvum and Giardia lamblia are some of the most commonly detected pathogens associated with diarrhea in humans.

The most common symptom of cryptosporidiosis is watery diarrhea. Other symptoms include:

  • Stomach cramps or pain
  • Dehydration
  • Nausea
  • Vomiting
  • Fever
  • Weight loss

Symptoms of cryptosporidiosis generally begin 2 to 10 days (average 7 days) after becoming infected with the parasite.

The most common symptom of Giardia is diarrhea. In some cases, people infected with Giardia have no symptoms. Other symptoms include:

  • Gas
  • Greasy stools that tend to float
  • Stomach or abdominal cramps
  • Upset stomach or nausea/vomiting
  • Dehydration (loss of fluids)

Symptoms of giardiasis normally begin 1 to 3 weeks after becoming infected. In children, severe giardiasis might delay physical and mental growth, slow development, and cause malnutrition.

Where and how does Giardia get into drinking water?

Millions of Giardia parasites can be released in a bowel movement of an infected human or animal. Human or animal waste can enter the water through different ways, including sewage overflows, sewage systems that are not working properly, polluted storm water runoff, and agricultural runoff. Wells may be more vulnerable to such contamination after flooding, particularly if the wells are shallow, have been dug or bored, or have been submerged by floodwater for long periods of time.

Tips to avoid parasitic infections

  • Wash your hands with soap and warm water.
  • Drink water from safe sources and use Berkey Water Filters.
  • Wash all raw fruits and vegetables under running water from a safe source.
  • If possible, use a vegetable brush to scrub the outside of fruits and vegetables.
  • If camping/hiking and safe water is not available, boil water for 1 minute before drinking or use Berkey Water Filters..
  • When swimming try not to swallow the water.
  • When drinking milk and juice, use only pasteurized products.
  • Be aware of public boil alerts and follow the recommendations.

Treating Cryptosporidium and Giardia


If you think you have cryptosporidium or giardia, this is what you should do.

  • Go to your doctor. They may ask to test a specimen of your faeces for cryptosporidium or giardia. Your doctor will give you advice on how to collect the specimen and what to do with it.
  • Take medicines if your doctor prescribes them.
  • There is no treatment for cryptosporidium, but there are medicines to help the symptoms.
  • There are treatments for giardia.
  • Drink plenty of water while you have diarrhoea or vomiting.
  • Go back to your doctor if you have a child that is ill and is not able to drink.
  • Stay away from school, early childhood centres or work until 48 hours (2 days) after the symptoms have gone.

Cryptosporidium and giardia are notifiable diseases – meaning that your doctor will inform the Medical Officer of Health of the Public Health Service (PHS). The PHS may contact you to find out how you were infected. This helps prevent more cases of the infection.


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