Pennsylvania (PA) has the second highest number of private water supply wells in the US, with approximately 3 million people relying on well water. Private wells are not regulated by the U.S. Environmental Protection Agency or any other authority, and thus the burden is on the homeowner to test and treat their water accordingly. Between 1971 and 2008, 30% of all waterborne outbreaks in the US were associated with the consumption of untreated groundwater. PA had the second highest number of outbreaks during this time period. The CDC recently identified that the burden of disease associated with private wells in the US is unknown and could be significant. Based on previous research, I estimate that there could be 81,000 cases of acute gastrointestinal illnesses (AGI) per year in PA due to private well water.