Tips on protecting your private drinking water well

Most Americans assume their tap water is safe to drink. But contamination of drinking water is a persistent problem in many communities throughout the country. Private wells are especially vulnerable to contamination since they tend to be shallow and are often close to residential or commercial development. Also, since private wells are not federally regulated, contaminated water often goes unnoticed. Researchers at Silent Spring Institute recently detected more than two dozen unregulated contaminants, including pharmaceuticals and consumer product chemicals, in private wells on Cape Cod.

If you are a private well owner, here’s what you can do to keep your drinking water safe:

Have your water tested. The Environmental Protection Agency (EPA) recommends having your water tested annually for nitrates and bacteria. If testing reveals nitrate levels greater than 1 ppm (mg/L), this is an indicator that your water may contain other contaminants like pharmaceuticals. You might want to test for arsenic, volatile organic compounds (chemicals found in gasoline and solvents), and pesticides as well since these are also common contaminants in private wells. 

Install a filter. If testing reveals nitrate levels greater than 1 ppm, consider installing a solid block carbon filtration system to remove contaminants that may have seeped into your well. Although it’s unknown if low levels of contaminants—pharmaceuticals, stain-resistant chemicals, and flame retardants—in drinking water pose a health risk, you can still take precautions to protect yourself and your family. If the test shows nitrate levels exceeding the EPA’s drinking water standard of 10 ppm, you will need to treat your water with a reverse osmosis or ion exchange system.

Create a clean buffer. Protect the land around your private well. Never dump hazardous materials such as pesticides, fertilizers, paint, or fuel oil in or around your yard.

Don’t flush it. Never pour unused or expired medications down the drain or flush them down the toilet. Proper disposal of medications is one way to keep pharmaceuticals from getting into the environment. However, keep in mind that much of the pharmaceuticals that enter household wastewater come from excretion from our bodies.

Know the source. Find out where your drinking water comes from. Check out local factors that might affect the quality of water in your well; farming activities, septic systems, landfills, and residential development can release harmful chemicals into groundwater. Help keep your drinking water clean and advocate for better protection of source water.

Choose less-toxic. By avoiding consumer products that contain harmful ingredients—carpets made with stain-resistant coatings or furniture with flame retardant chemicals—you can reduce the amount of toxic chemicals entering your household wastewater. Consult Silent Spring’s mobile app Detox Me to find out how to eliminate toxic chemicals from your daily life.

For more information about private drinking water wells, visit You can also learn more about Silent Spring’s water quality research at

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