Tuesday, May 8, 2012
About One-Third of Drinking Water Wells are Contaminated with Bacteria
Homeowners often don't know the quality of the water they are drinking, and an estimated one third of their wells are contaminated with bacteria.
About one quarter of homes in Franklin County get their drinking water from private wells.
Typically only half of homeowners ever have their water tested, and then only once, according to Penn State Extension Educator Thomas Richard McCarty.
"The major risk for most people is contamination from bacteria," he said. "This is hidden both from sight and taste. Health effects may be hidden too by building resistance to the presence of bacteria, which suffices as long as bacteria counts are low and the householders are in generally good health. Symptoms properly due to poor water may easily be blamed on something else."
Penn State Extension is offering discounted water testing kits this week.
According to Penn State Extension data for well water in Franklin County:
-- About 35 percent of private wells have coliform bacteria in their water. Coliform bacteria come from soil, sewage, or manure and enter groundwater from heavily fertilized areas - home lawns, farm fields or septic systems.
-- One in 10 has fecal coliform levels exceeding safe drinking water standards. This branch of the coliform family includes the dreaded E. coli.
-- One of every six have nitrates above the limit for drinking water. Nitrate is of concern when infants under six months drink the water or older people with stomach problems.
-- One of every 13 homes supplied by a well has lead levels exceeding the maximum allowable concentration. Children absorb more of the lead in their diet than adults do. Lead in water comes primarily from solder joints in copper pipe. Exposure to high levels of lead can result in delays in physical and mental development, along with slight deficits in attention span and learning abilities. Adults exposed to lead over a number of years can develop high blood pressure or kidney problems.
"The lack of testing by well owners is not for a lack of concern over their water quality, but instead, a lack of awareness and understanding of what testing should be done," according to a 2009 Penn State study Drinking Water Quality in Rural Pennsylvania. "The great majority of well owners that were told of health-related water quality issues in their water supply had voluntarily solved the problem within one year."
A deeper well does not always have purer water. Limestone bedrock has more to do with bacterial contamination of wells than does the depth of the well, according to a 2001 U.S. Geological Survey study of wells in south-central Pennsylvania. Bacterial concentrations actually increased with depth to the waterbearing zone in limestone. Many of the wells in
Franklin County are drilled in limestone geology.
Franklin County lacks current data on the use of private wells.
"The 1980 Census reported that 63 percent of homes were on public water," said Phil Tarquino, chief of the county planning department. "The remaining 37 percent were on drilled wells, dug wells or cisterns. It would seem that the percent of homes on public water has increased in the last 30 years as most new development has occurred in areas where public water is located. In addition public water has been extended to areas that were previously on wells or cisterns."
Pennsylvania has more residents using private wells than any other state, except Michigan, and each year another 20,000 are drilled, according to Penn State's manual for well owners.
McCarty said he is at a loss to explain why interest in Penn State's water testing program has declined of the years. A steeply discounted program in Adams County attracted few participants.