Bacterial contamination

Percentage of domestic wells in New Jersey that were positive for bacteria (after Worthington et al., 2016)

Flow in bedrock is bedrock aquifers is generally more rapid than in unconsolidated sediments, so it not surprising that microbial contamination in bedrock aquifers is often two to three times more common than in unconsolidated sediments, as shown for instance by the figure, based on data from >50,000 wells in New Jersey, USA