Aquifers of the United States
Regional groundwater systems that feed America's private wells.
An aquifer is a geologic formation that holds and transmits water. If you drill a well, you're drilling into one. This list covers the major aquifer systems that supply private wells in the US — and the ones where water quality or quantity issues are most pronounced.
The deep confined sand-and-gravel aquifer system underneath the Mississippi Alluvial Valley — a separate Tertiary stack below the Quaternary alluvium. Memphis…
The folded Appalachian aquifer system from central Pennsylvania through northwestern Alabama. Carbonate valleys host karst aquifers with high yields and high vu…
The aquifer system underneath the Gulf coastal lowlands from East Texas through Louisiana, Mississippi, Alabama, and into the Florida Panhandle. Hosts America's…
The aquifer system underneath the Ozark Plateaus of Missouri, northern Arkansas, and adjacent eastern Oklahoma. Karst limestone with extensive cave development;…
The basaltic aquifer system underneath the Columbia Plateau — Eastern Washington, northeastern Oregon, parts of Idaho. Supplies irrigated agriculture (apples,…
Granite, gneiss, schist, and quartzite of the Piedmont and Blue Ridge provinces — the eastern flank of the Appalachians from northern Georgia through Maryland…
A wedge-shaped stack of confined sand-and-gravel aquifers underlying the coast from Long Island to North Carolina. Supplies drinking water to about 18 million p…
The aquifer system underneath the Basin and Range Province — Nevada, western Utah, southern Arizona, parts of New Mexico and southeastern Oregon. Each topogra…
The Eastern Snake River Plain Aquifer is one of the most productive aquifers in North America — a 10,000-square-mile sheet of fractured basalt holding water t…
An ancient sandstone-and-carbonate aquifer system underneath the Upper Midwest — supplying drinking water to Madison, Minneapolis-St. Paul, Iowa City, and mil…
California's 400-mile-long agricultural valley sits on a stack of alluvial aquifers that have been mined for irrigation for a century. The land is sinking — o…
The Edwards is the most rapidly recharging major aquifer in the United States — water that falls in the recharge zone reaches deep wells within days. That spe…
The shallow alluvial aquifer beneath the Mississippi River's flood plain — Arkansas's rice belt, Mississippi Delta, Louisiana parishes. The most pumped aquife…
The principal drinking-water source for nearly all of Florida, southern Georgia, and parts of Alabama and South Carolina — about 10 million people. Karst geol…
Granite, granitic gneiss, and metamorphic bedrock across northern New England carry uranium-bearing minerals that weather into a notoriously bad cocktail: simul…
The largest aquifer in the United States and the source of about 30% of US irrigation. Being drawn down at roughly six times the rate it recharges. Some Texas a…
Four-layer bedrock aquifer system under Colorado's Front Range, supporting hundreds of thousands of private wells. Being drawn down faster than it recharges.