Most countries provide the public with easily available tap water drinking stations, and this water is usually considered safe for consumption. The government and health bodies have a testing and treatment process in place to ensure that tap water meets regulatory standards provided by them. However, water can have a certain potential to cause harmful side effects for people. Here are some reasons why one must avoid drinking tap water and switch to purified water. Microbial contamination Improper treatment of drinking water can lead to the water being contaminated with parasites like bacteria and viruses. And prolonged exposure to these microbes can lead to health issues like stomach cramps, diarrhea, and vomiting.  Fluoride exposure Fluoride is added to drinking water sources to prevent dental decay. However, if there is an excess amount of fluoride present in the water source, it can also cause dental fluorosis. The condition can cause defects in tooth enamel and lead to discoloration of the teeth. Increased intake of fluoride can also increase the risk of skeletal fluorosis, leading to symptoms like bone pain, stiffness, and fractures. Exposure to nitrates and nitrites Groundwater sources can turn septic because of system leakage. It can be caused because of the introduction of nitrates and nitrites in the water.