Farms, More Productive Than Ever, Are Poisoning Drinking Water in Rural America

Chuck Wagner has given up on drawing clean water from his faucets. When he moved, 23 years ago, to 80 acres situated between dairy farms in northeastern Wisconsin, he built a home and drilled a 123-foot well. The water tested clean, and his family drank it. Five years later, tests showed it was contaminated with bacteria and nitrates, potentially harmful and often derived from nitrogen in manure and fertilizer.One in seven Americans drink from private wells, according to the U.S. Geological Survey. Nitrate concentrations rose significantly in 21% of regions where USGS researchers tested groundwater from 2002 through 2012, compared with the 13 prior years. The greatest increases were in agricultural areas. More recent sampling shows the pattern is continuing, at a potentially greater rate.Meanwhile, more than 16% of groundwater from wells sampled between 2002 and 2012 topped the federal nitrate limit of 10 parts per million, versus 12% in the 1990s. The percentage above the limit fell slightly in the wells sampled after 2013 but remained elevated.“The worst-kept secret is how vulnerable private wells are to agricultural runoff,” says David Cwiertny, director of the University of Iowa’s Center for Health Effects of Environmental Contamination.Land researchers are urging farmers to change cultivation practices to cut water contamination. That includes sowing “cover crops” to hold soil in place between plantings and adding buffers of fallow land along field edges.