I am working with a small community that has one active well, which went into service in 2009. At that time, its water quality had similar characteristics of other wells in the area: about 350 mg/L calcium carbonate hardness, 260 mg/L total alkalinity, 0.6 mg/L iron, and 0.97 mg/L fluoride. By 2013, its fluoride increased to 2.10 mg/L; and by 2016, calcium carbonate hardness dropped to only 35 mg/L, total alkalinity soared to 859 mg/L, iron dropped to 0.03 mg/L, and fluoride rose to 3.17 mg/L. Research has found no news of a chemical spill in the area during these years, and geologists have been unable to explain this phenomenon. What could cause a groundwater source to change so drastically, as if the aquifer were softening itself with hardness and metal dropping and alkalinity soaring?