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Gaps in Federal and State Laws Leave Private Well Users Vulnerable to Drinking Water Contamination

April 9, 2019


Most people in the U.S. take access to a clean water supply for granted, without considering the source, or safety, of their drinking water. But there are distinct differences in how our laws do (or don’t) protect us from drinking water contamination. Household water that runs from our taps – including water used for drinking, cooking, and bathing – comes from either a public water system or a private well. While a landmark federal law, the Safe Drinking Water Act, generally protects individuals who use a public water supply from exposure to unsafe levels of regulated contaminants, there is no similar protection for the approximately 45 million U.S. residents who rely on private wells for water.

This gap in regulatory oversight increasingly burdens rural households, where the risk of exposure to nitrate contamination from commercial nitrogen fertilizer and animal manure from confined animal feeding facilities is highest. When contamination is found to be fouling private well water, the burden of obtaining a clean source of household water often falls on the well user – regardless of the source of contamination. Recent testing shows alarming numbers of rural private wells are contaminated by nitrate, which can cause a dangerous condition in infants and pregnant women called blue baby syndrome. Longer term exposure to nitrates in drinking water have been linked to certain cancers, thyroid problems, and neural tube defects.

Similarly, state laws or regulations may also lack protections for private drinking water sources. Minnesota’s recent effort to control one major source of nitrate contamination – commercial fertilizer – is illustrative. Nitrate contamination in Minnesota’s vulnerable agricultural regions threatens both public and private drinking water sources. A recent study of 306 vulnerable agricultural townships produced distressing results: in 135 townships more than 10 percent of private wells tested had unsafe nitrate levels. However, the Minnesota Department of Agriculture’s (MDA) recently adopted “groundwater protection rule” applies measures to mitigate nitrate contamination – such as fertilizer use recommendations, alternative cropping systems, or cover crops – but only where a public water supply is threatened.

Why were private wells left out? It’s not a lack of statutory authority – MDA admittedly has the authority to control sources of nitrate contamination in private wells. Indeed, prior proposed drafts of the rule included measures to reduce nitrate contamination in both public wells and in townships where more than 10 percent of private wells are contaminated. And the rule also includes a statewide ban on commercial fertilizer application in the fall and on frozen ground in areas vulnerable to contamination. But a lack of resources and the large land expanse – over 1 million cropland acres – contributing to concentrated areas of private well contamination led MDA to trim those township focused source reduction measures from the rule. Concerns remain that the pared back rule inequitably excludes private wells from source reduction requirements, which, as the Minnesota Department of Health noted, “does not serve the public health needs of rural Minnesotans.” While some private well owners may see ancillary benefits from the seasonal application restrictions and mitigation efforts to protect public water supplies, the state rule largely mirrors the gap in federal protections for private drinking water sources.

Without strong federal and state laws to protect private well users from exposure to contamination, local health departments are often the first line of defense. Many local governments help homeowners test their drinking water quality. Local ordinances may also regulate well drilling, and local health departments may seek regulatory tools to mitigate, or stop, sources of private well contamination. More broadly, the National Association of County and City Health Organizations advised federal, state, and local officials to adopt policies to address, among other things, one major source of nitrate groundwater contamination – manure disposal from concentrated animal feeding operations. Some local officials, where not preempted by state law, are doing just that:

  • In Winona County, MN, where many private wells are contaminated, a county ordinance limits the number of animals (equivalent to about 1000 dairy cows) housed at a concentrated animal feeding operation.
  • In Saratoga, WI, an area susceptible to contamination from manure leaching through sandy soils, the town can require a person engaged in the land application of manure to propose measures to remediate high nitrate levels, and can also require groundwater sampling, changes to land application procedures and manure disposal, and remedial action to restore groundwater quality or minimize future contamination.

Until the gap in regulatory oversight is filled – by federal, state, or local government – many rural U.S. residents risk increased exposure to contaminated drinking water. Private well testing is an essential first step in understanding the risk of exposure to contaminants, but eliminating the source of contamination will require focused efforts to collect data, understand sources and solutions, and build sustained political will for change.

The Network provides information and technical assistance on issues related to public health. The legal information and assistance provided in this document does not constitute legal advice or legal representation. For legal advice, readers should consult a lawyer in their state.

Support for the Network is provided by the Robert Wood Johnson Foundation (RWJF). The views expressed in this post do not necessarily represent the views of, and should not be attributed to, RWJF.