(As Certified by NSF International on October 1, 1994)
| Contaminant | Type of Contaminant | Health Effects |
| Alachlor | Herbicides/Organic | Cancer. Affects nervous system |
| Asbestos | Inorganic | Cancer |
| Atrazine | Herbicides/Organic | Cancer, affects nervous system and mammary glands |
| Benzene | VOC | Cancer, leukemia, and anemia |
Bromodichloromethane (TTHM) | VOC/THM | Affects nervous system and muscles. Probable cause of cancer |
Bromoform (TTHM) | VOC/THM | Affects nervous system and muscles. Probable cause of cancer |
Carbofuran (Furadan) | Pesticides/Organic | Nervous system, kidneys and liver. Causes anemia and leukemia. Probable cancer. Preproductive system effects |
| Carbon Tetrachloride | VOC | Cancer |
Chlorobenzene (Monochlorobenzene) | VOC | Affects nervous system, liver and kidneys |
Chloroform (TTHM) | VOC/THM | Affects nervous system and muscles. Probable cause of cancer |
| Cryptosporidium | Human & animal fecal waste | Gastroenteric diseases |
Cysts / Organisms (Giardia, Protozoan, Cryptosporidium) | Human & animal fecal | Gastroenteric diseases |
| 2,4D | Pesticides/Organic | Affects liver and kidney damage |
DBCP (Dibromochloropropane) | Fumigant | Reproductive effects |
Dibromochloromethane (TTHM) | VOC/THM | Affects nervous system and muscles. Probable cause of cancer |
1,2-Dichlorobenzene (o-Dichlorobenzene) | VOC | Affects kidneys, liver and lungs |
p-Dichlorobenzene (Dichlorobenzene) | VOC | Cancer |
1,1-Dichloroethane (1,1-DCA) | VOC | Liver, kidney and nervous system |
1,2-Dichloroethane (1,2-DCA) | VOC | Causes damage to kidneys & liver. Can cause nausea |
Trans-1,2- Dichloroethylene | VOC | Pending Study |
1,1-Dichloroethylene (1,1-DCE) | VOC | Cancer, liver and kidneys |
| cis 1,2-Dichloroethylene | VOC | Liver, circulatory system, central nervous system, and kidneys |
1,2-Dichloropropane (Propylene Dichloride) | VOC | Cancer, liver and kidneys |
Cis-1,3- Dichloropropylene | Pesticides | Damage to bladder and kidneys |
| Dinoseb | Pesticides/Organic | Reproductive organ damage, thyroid |
| Endrin | Pesticides/Organic | Affects nervous system, kidneys and liver. Causes anemia and leukemia. Probable cause of cancer and heart damage |
| Ethylbenzene | Organic | Affects nervous system, liver and kidneys |
Ethyl Dibromide (EDB) | Pesticides | Possible reproductive effects or damage to target organs |
Giardia Lamblia (Cysts, Protozoan) | Human & animal fecal waste | Gastroenteric disease |
Hexachlorobutadiene (Perchlorobutadiene) | VOC | Pending study |
Hexachloro- cyclopentadiene | VOC | Pending study |
| Lead (pH 6.5) | Inorganic | Nervous system; kidneys, highly toxic to infants and pregnant women |
| Lead (pH 8.5) | Inorganic | Nervous system; kidneys, highly toxic to infants and pregnant women |
| Lindane | Pesticides/Organic | Nervous system and liver. Affects kidneys |
| Meta-Xylene | Pesticides | Affects nervous system, kidneys, lungs, liver and mucous membranes |
| Methoxychlor | Pesticides/Organic | Nervous system, kidneys and liver. Anemia and leukemia. Probable cause of cancer |
Methylbenzene (Toluene) | VOC | Affects nervous system, liver and kidneys |
| Ortho-Xylene | Pesticides | Affects nervous system, kidneys, lungs, liver and mucous membranes |
| Para-Xylene | Pesticides | Affects nervous system, kidneys, lungs, liver and mucous membranes |
| Pentachlorophenol | Organic/Herbicides | Liver and kidneys. Probable cause of cancer |
| Simazine | Organic/Herbicides | Cancer, affects nervous system |
| Styrene | VOC | Nervous system, liver and kidneys |
1,1,2,2- Tetrachloroethane | VOC | Pending study |
| Tetrachloroethylene | VOC | Affects nervous system. Probable cause of cancer |
Toluene (Methylbenzene) | VOC | Affects nervous system, liver and kidneys |
2,4,5-TP (Silvex) | Pesticides | Liver and kidney damage. Affects nervous system, probable cause of cancer |
| 1,2,4-Trichlorobenzene | Pesticide | Liver & kidney damage |
1,1,1-Trichloroethane (1,1,1-TCA) | VOC | Liver, nervous system effects |
| 1,1,2-Trichloroethane | Pesticide | Pending study |
Trichloroethylene (TCE) | VOC | Cancer |
Trihalomethanes (TTHM; Chloroform; Bromoform; Bromodichloromethane; Dibromochloromethane) | VOC/Disinfection by-product | Affects nervous system and muscles. Probable cause of cancer |
| Turbidity | Coloform and surface water treatment | Interferes with disinfection, related to increased disinfection by-products |