Why are water supplies tested for Cryptosporidium?

Water supplies are tested for Cryptosporidium because it is a dangerous parasite that can contaminate drinking water sources, including artesian wells.1

Testing is a critical component of water purification and quality control, as government agencies establish standards to limit the concentration of harmful microbial pathogens in public water supplies. Because water quality cannot be determined by appearance alone, rigorous biological analyses are necessary to detect such contaminants. Ensuring the absence of pathogens like Cryptosporidium is essential for public health, as the consumption of unsafe water is a primary cause of diarrheal diseases, which contribute significantly to global illness and mortality.1