Water tower for public supply in Clayton, NJ

Groundwater is pumped from a public-supply well and stored in a water tower for residents' use in Clayton, New Jersey. The well taps groundwater from the North Atlantic Coastal Plain aquifer.

Groundwater in the Atlantic and Gulf Coastal Plain aquifers is old—more than 21,300 years old in more than half of the wells sampled. That ancient groundwater is more likely to contain naturally occurring concentrations of fluoride, arsenic, and polonium-210 that exceed a human-health benchmark for drinking water than younger groundwater, reports a study from the U.S. Geological Survey National Water Quality Program.