reverse osmosis banner squareArsenic occurs naturally in rocks and soil, water, air, and plants and animals. It is odorless and tasteless. It can be further released into the environment through natural activities such as volcanic action, erosion of rocks and forest fires, or through human actions. Approximately 90 percent of industrial arsenic in the U.S. is currently used as a wood preservative, but arsenic is also used in paints, dyes, metals, drugs, soaps and semi-conductors. High arsenic levels can also come from certain fertilizers and animal feeding operations. Industry practices such as copper smelting, mining and coal burning also contribute to arsenic in our environment.

At Risk From Arsenic

Quote Left Arsenic is potentially hazardous at high levels for private well owners. Quote Right

Higher levels of arsenic tend to be found more in ground water sources than in surface water sources (i.e., lakes and rivers) of drinking water. The demand on ground water from municipal systems and private drinking water wells may cause water levels to drop and release arsenic from rock formations. Like many contaminants that enter drinking water supplies, arsenic is potentially hazardous at high levels for private well owners. Because you cannot see or taste arsenic in water, it is up to the well owner to test for arsenic. Compared to the rest of the United States, western states have more systems with arsenic levels greater than EPA’s standard of 10 parts per billion (ppb). Parts of the Midwest and New England have some systems whose current arsenic levels are greater than 10 ppb, but more systems with arsenic levels that range from 2-10 ppb. While many systems may not have detected arsenic in their drinking water above 10 ppb, there may be geographic "hot spots" with systems that may have higher levels of arsenic than the predicted occurrence for that area.

Health Effects

Human exposure to arsenic can cause both short and long term health effects. Short or acute effects can occur within hours or days of exposure. Long or chronic effects occur over many years. Long-term exposure to arsenic has been linked to cancer of the bladder, lungs, skin, kidneys, nasal passages, liver and prostate. Non-cancer effects can include thickening and discoloration of the skin, stomach pain, nausea, vomiting, diarrhea, numbness in hands and fee, partial paralysis, and blindness. But, such effects are unlikely to occur from U.S. public water supplies that are in compliance with the arsenic standard. However, it is best to consult your local health department about this situation and ask about your area. You may also wish to talk with your state geological survey office or USDA agent.


EPA has set the arsenic standard for drinking water at 0.010 parts per million (10 parts per billion) to protect consumers served by public water systems from the effects of long-term, chronic exposure to arsenic. Water systems must comply with this standard by January 23, 2006, providing additional protection to an estimated 13 million Americans. This standard applies to all 54,000 community water systems. EPA estimates that roughly five percent, or 3,000 community water systems serving 11 million people, will have to take corrective action to lower the current levels of arsenic in their drinking water. The revised standard will also apply to the 20,000 non-community water systems that serve at least 25 of the same people more than six months of the year, such as schools, churches, nursing homes, and factories. EPA estimates that five percent, or 1,100 of these water systems, serving approximately 2 million people, will need to take measures to meet the revised standard.

Test the Arsenic level

If your water comes from a municipal or privately owned water company that has more than 15 service connections or serves 25 people more than 6 months of a year, they are already testing for arsenic in your water. If you own your own, individual well, you are responsible for testing it. Contact your local health department or state certified laboratory in your local area for water testing.

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