| Group | Contaminants |
| Microorganisms | Giardia lamblia, Cryptosporidium, Legionella, Total Coliform (including E. coli and fecal coliform), and viruses |
| Radionuclides | Alpha and Beta particles, Radium 226 and 228, and uranium |
| Organic Chemicals | Acrylamide, alachlor, atrazine, benzene, carbofuran, carbon tetrachloride, chlordane, chlorobenzene, dalapon, various forms of dichlorobenzene, dichloroethane, dichloroethylene, dichloromethane, dichloropropane, dinoseb, dioxin, diquat, endothall, endrin, epichlorohydrin, ethylbenzene, ethylene dibromide, glyphosate, heptachlor, hexachlorobenzene, lindane, methoxychlor, osamyl, polychlorinated biphenyls, pentachlorophenol, picloram, simazine, styrene, tetrachloroethylene, toluene, toxaphene, various forms of trichlorobenzene, trichloroethane, trichloroethylene, vinyl chloride and xylenes. |
| Inorganic Chemicals | Antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, copper, cyanide, fluoride, lead, mercury, nitrate, nitrite, selenium and thallium. |
| Disinfectants | Chloramines, chlorine, and chlorine dioxide. |
| Disinfectant Byproducts | Bromate, chlorite, haloacetic acids and total trihalomethanes (bromoform, chloroform, bromodichloromethane, dibromochloromethane) |