Arsenic, a toxic metalloid in Group 15 of the periodic table, is associated with chronic and acute health effects due to its ability to inhibit enzymes associated with adenosine tri-phosphate (ATP) production, resulting in multi-organ damage and carcinogenic effects. The risks from exposure to low concentrations of arsenic in drinking water are not well documented. This thesis investigated the cancer risks to human health associated with lifetime consumption of groundwater contaminated with low concentrations of arsenic. In order to test my hypothesis, I utilized analytical techniques including risk assessment, geographic information system (GIS) software tools that integrate hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information, and Standardized Incidence Ratios (SIRs) for bladder cancer in two counties in north central Massachusetts. I reviewed the results of these assessments through a series of comparisons. My study found that bladder and urinary cancer incidence rates obtained from the Massachusetts Cancer Registry for selected towns where people drink water that is likely to contain more than 10 μg/liter arsenic were not related to arsenic concentration in the bedrock aquifer, but my risk assessment demonstrated that there is possible increased risk. Further research on levels of arsenic in untreated private well drinking water is needed for conclusive results.