Faucets with filtering devices appeared to reduce arsenic levels in Hernando County homes known to have tainted well water. The four-month Department of Health study compared urine levels of residents in homes with arsenic-laced wells to those whose wells had safe levels, according to the Tampa Bay Times. Once filters were added to kitchen faucets, researchers found only a marginal difference in the arsenic levels between the two groups. High concentrations of arsenic have been found in Hernando groundwater, mostly in rural areas where the pesticide was used for farming. In Florida, 20 percent of its population depends on water from underground wells.