Most sources of fresh, drinking water aren’t exactly clean. Disregarding pollution and human activity, these bodies of water can become contaminated by naturally-occurring substances like selenium and mercury. It is important for residential and commercial establishments to make sure that their water supplies are properly filtered and inspected, even if the local water treatment facility is doing its job.
The Environmental Protection Agency (EPA) has six classifications for contaminants that can be found in water supplies. Microorganisms like Cryptosporidium and Legionella are usually present in water sources polluted with fecal matter that can cause gastrointestinal diseases. Organic and inorganic chemicals, meanwhile, are found in water sources situated near factories, farms, and chemical plants. Some chemicals like chlorobenzene can be found well away from the source of pollution.
Radionuclides, on the other hand, are natural contaminants produced by the erosion of radioactive deposits in the soil. Some examples noted by the EPA are radium and uranium, which can increase the risk of cancer when ingested. By contrast, disinfectants and disinfection byproducts are manmade chemicals found in water supplies treated with certain cleaning agents. These contaminants can cause mild skin or eye irritation and anemia, the severity of which depends on the amount consumed.