Water systems that have ground water sourced may be susceptible to fecal contamination. In many cases, fecal contaminations can contain disease causing pathogens. The GWR will provide increased protection against microbial pathogens” (water.epa.gov). “Why is EPA taking a risk-based approach to protect drinking water provided by ground water systems? An evaluation of data on outbreaks and the occurrence of waterborne viral and bacterial pathogens and indicators of fecal contamination in ground water supplying public water systems (PWS) wells indicate that there is a subset of ground water systems (GWS) that are susceptible to fecal contamination” (water.epa.gov).