September 15, 2009
I recently purchased a country home with well water and a septic system. We had the water tested for bacteria and it has tested negative several times. My question is, is well water that is free of contaminants and bacteria safer to drink then chlorinated city water?
This is a difficult question to answer because the science about the health risks of chlorinated water exposure is inconclusive. There are studies that have linked the byproducts of chlorination with a slight increase in bladder cancer and other health risks, but the findings are disputed because they are inconsistent.[1-5]
At the present time, chlorine is not classified as a possible, probable or known carcinogen. The advantage to having chlorinated water is that it decreases your risk of contracting water borne illness because the chlorination of the water prevents most bacteria, viruses, and parasites from surviving. The major risk of a non-municipal well is contamination by microorganisms and chemicals, so it is critical to maintain your well properly.
Even though there are no bacteria in your well, you should also have periodic testing done for heavy metals, parasites, nitrates, radon and other hazardous chemicals to make sure that your water is safe to drink. The EPA is a great resource for information about keeping your private well water safe - try their Private Drinking Water Wells website.[6]
As for the comparative safety of chlorinated versus well water, even though the health risks of chlorine are not definitive, EPA does limit the amount of chlorination in water. Overall, based on the risk of well contamination and the risk of chlorine harming you, the relative risk is probably comparable.
At the present time, chlorine is not classified as a possible, probable or known carcinogen. The advantage to having chlorinated water is that it decreases your risk of contracting water borne illness because the chlorination of the water prevents most bacteria, viruses, and parasites from surviving. The major risk of a non-municipal well is contamination by microorganisms and chemicals, so it is critical to maintain your well properly.
Even though there are no bacteria in your well, you should also have periodic testing done for heavy metals, parasites, nitrates, radon and other hazardous chemicals to make sure that your water is safe to drink. The EPA is a great resource for information about keeping your private well water safe - try their Private Drinking Water Wells website.[6]
As for the comparative safety of chlorinated versus well water, even though the health risks of chlorine are not definitive, EPA does limit the amount of chlorination in water. Overall, based on the risk of well contamination and the risk of chlorine harming you, the relative risk is probably comparable.
- King WD, Marrett LD. Case-control study of bladder cancer and chlorination by-products in treated water (Ontario, Canada). Cancer Causes and Control. 1996;7(6):596-604.
- Cantor KP, Lynch CF, Hildesheim ME, Dosemeci M, Lubin J, Alavanja M, Craun G. Drinking Water Source and Chlorination Byproducts: I. Risk of Bladder Cancer. Epidemiology. 1998;9(1):21-28.
- Suzuki T, Masuds M, Friesen MD, Fenet B, Ohshima H. Novel products generated from 2''-deoxyguanosine by hypochlorous acid or a myeloperoxidase-H2O2-Cl- system: identification of diimino-imidazole and amino-imidazolone nucleosides. Nucleic Acids Research. 2002;30:2555-2564.
- Morris RD. Drinking water and cancer. Environmental Health Perspectives. 1995;103(Suppl. 8):225-232.
- Reif JS, Hatch MC, Bracken M, Holmen LB, Schwetz BA, Singer PC. Reproductive and developmental effects of disinfection by-products in drinking water. Environmental Health Perspectives. 1996;104:1056-1061.
- Environmental Protection Agency
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