Agricultural Sciences

Statewide study of well owners reveals good news, bad news

University Park, Pa. — A two-year, statewide study of private water wells by Penn State Cooperative Extension has revealed both good news and bad news about much of the state's drinking water.

First the positives: The levels of lead and nitrates in wells seem to have fallen sharply in the last 25 years, and well owners are generally happy with their water supplies. The negatives? Forty percent of the more than 700 wells tested failed to meet the state's safe-drinking-water standards for at least one contaminant. And most of the people with contaminated wells were unaware that they had a problem.

“It was encouraging to see that some contaminants were less common and overall pollution of wells does not appear to be getting worse over the past two decades," said Brian Swistock, extension water resources specialist. "But to see that four out of every 10 wells still had problems was discouraging. We were surprised to learn that most of the people with contaminated wells had no idea that there were problems with their water. That's probably because the pollutants we tested for create no obvious tastes, stains or odors in water, so the only way to detect them is by getting the water properly tested at a certified laboratory."

Contamination of drinking water in private wells is a major issue in Pennsylvania. The Keystone State has 3 million people relying on more than 1 million private wells for drinking water — second only to Michigan. But the Commonwealth is one of only two states that does not mandate construction standards for wells. About 20,000 new wells are drilled every year in Pennsylvania.

"In the study, which was mainly funded by the Center for Rural Pennsylvania, we found that well construction has a major determining effect on some well pollutants," said Swistock. "We were able to document that wells of poor construction had poor water quality -- so it does make a difference."

Swistock explained that other states require sanitary well caps with a cement-like grout seal around the well casing, which keeps animals, insects and surface water from getting into the wells. "Grout seals make a huge difference in keeping bacteria associated with the surface from getting into the well water," he said.

The wells in the study were tested for coliform bacteria, E. coli bacteria, lead, arsenic, triazine pesticides and nitrates. The pH levels also were sampled. The drop in lead and nitrate levels indicate regulations and educational efforts are paying off, according to Swistock. More than a decade ago, the federal government banned the use of lead in plumbing systems in new construction, which has resulted in the incidence of lead in wells being about half of what it was in 1993, the last time a statewide survey was done.

"The incidence of less nitrate is harder to explain but may be a result of nutrient-management efforts by the agricultural community," Swistock said. "We found only 2 percent of the wells we surveyed had an incidence of nitrate above safe-drinking-water standards. That compares to 12 percent in 1993 and about 14 percent in the mid-1980s."

The fact that many homeowners are not aware of pollution problems in their well water is a major concern, Swistock contends, because contaminants could be making them sick. That's why Cooperative Extension repeatedly urges well owners to get their water tested. "We have recommended to the General Assembly that there should be some sort of requirement to test well water when a real estate transaction takes place or when a well is drilled, or both, so that homeowners are aware of these problems," he said.

The study would have been prohibitively expensive were it not for extension's Master Well Owner Network, Swistock pointed out. "We had 172 volunteers help with this study, which was also funded by the Pennsylvania Water Resources Research Institute. Without the involvement of the Master Well Owner volunteers and their sponsor agencies (Pennsylvania Department of Environmental Protection and U.S. Department of Agriculture), the study would have cost at least five times as much and might have not been possible," he said.    

For more information on the study, visit the Center for Rural Pennsylvania's Web site ( and click on "Drinking Water Quality in Rural Pennsylvania and the Effect of Management Practices."

Last Updated March 19, 2009