THE CONNECTION BETWEEN THE QUALITY OF WATER AND POTENTIAL COST TO THE CONSUMER FOR WATER SUPPLIES FROM THE GLACIAL AQUIFER SYSTEM
In agricultural areas where tile drains are used to lower the water table and make land arable, tile drains intercept groundwater and contaminants near the water table and redirect them to rivers. An unintended consequence is that public-supply wells near rivers capture those river-borne contaminants, through induced infiltration. If the contaminants captured reach levels that require additional treatment, the cost of treatment can increase.
Arsenic, derived from geologic sources, also affects drinking water in the glacial aquifer. Treating water to reduce arsenic concentrations to values lower than the MCL comes at an increase in costs to consumers. About 11 percent of domestic well users (or an estimated 1 million people) have arsenic greater than 10 micrograms per liter; however, this number would increase to an estimated 2.5 million if a standard of 3 were adopted and to an estimated 4 million if the standard was lowered to 1 microgram per liter. Additionally, the costs to consumers are higher proportionally for smaller suppliers than for larger ones, further increasing the costs.
In addition, nuisance constituents in groundwater often limit water use, particularly in private wells. Three-quarters of samples from drinking-water wells contained nuisance constituents, such as iron, manganese, chloride, sodium, sulfate, and aluminum, at concentrations exceeding the Secondary Maximum Contaminant Levels set by the U.S. Environmental Protection Agency. Although the glacial aquifer system provides a plentiful supply of groundwater, these constituents cause many consumers to abandon their well water and purchase drinking water costing hundreds of dollars per year. Additionally, deposits in pipes and corrosion add to costly home repairs.