Maryland is sitting on ancient water.
Some of the groundwater in the upper Patapsco aquifer is more than a million years old, according to the U.S. Geological Survey.
"Groundwater age indicates the length of time that a sample of water has been in the ground since infiltrating from the land surface," the U.S. Geological Survey says in a news release
. "This study reveals that modern pumping in southern Maryland west of the Chesapeake Bay and on the Eastern Shore is tapping groundwater resources that have accumulated in the aquifer over multiple cycles of climate change and are not quickly recharging."
There are few aquifers in the world containing million-year-old groundwater, according to the USGS. They include the Nubian aquifer in the Sahara Desert, Canada's Alberta Basin and the Great Artesian Basin in Australia.