Cryptosporidium infection can be caused by swallowing only a small amount of cryptosporidia. Swallowing this water when swimming or drinking it may cause cryptosporidiosis. Drinking water or ice may also contain cryptosporidium. Cryptosporidium is in many of the lakes and rivers that provide drinking water in the United States. Unlike most germs and one-celled animals, cryptosporidium is not killed by the chlorine used to treat drinking water.
Boiling water is the best method of killing cryptosporidium.
Water should be brought to a rolling boil for one full minute. After the boiled water cools, it can be stored in a clean, sealed bottle or pitcher with a lid and used normally. Individuals should be careful not to touch the inside of their water bottles. Water can also be filtered to remove cryptosporidium. Persons drinking bottled water should look for evidence of these treatments on the bottled water label, or buy distilled water.