Abstract: Longevity, as a complex life-history trait, shares an ontogenetic relationship with otherquantitative traits, such as epigenetic and environmental factors. Therefore, it is important toidentify environmental factors that may modify the epigenome to establish healthy aging. This studyexplored the association between tap drinking water and longevity in Cilento, Italy, to understandwhether trace elements in local drinking water may have an influence on old, nonagenarian, andcentenarian people and promote their health and longevity. Data on population and water sourceswere collected through the National Demographic Statistics, the Cilento Municipal Archives, andthe Cilento IntegratedWater Service. Ordinary least squares (OLS) regression and a geographicallyweight regression (GWR) model were used to study the spatial relationship between the explanatoryand outcome variables of longevity. The results of the study showed that the prevalence of longevityis concentrated in the central, northern and southeastern areas of the territory and that some traceelements present in tap water may contribute to local longevity in Cilento. Specifically, all Cilentomunicipalities had alkaline tap water, and the municipalities with the highest longevity concentrationshad higher alkalinity levels than the other municipalities, soft to medium-hard water hardness, anamount of total dissolved solids equivalent to the level of excellent water, lower amounts of sodium,adequate iron concentration, and adequate dietary intake of manganese per day.