Cambrian-Ordovician Aquifer System
5 states · 400,000 sq km · confined
Moderate Risk
About the Cambrian-Ordovician Aquifer System
The Cambrian-Ordovician system is a major confined aquifer spanning the upper Midwest. The St. Peter Sandstone and Jordan Sandstone are among the most productive water-bearing units.
Area
400,000 km²
Depth Range
500–2,500 ft
States
5
Rock Type
Sandstone
Key Facts
- ▸Supplies many Midwest cities including parts of Chicago and St. Louis
- ▸Deep confined aquifer with very slow recharge
- ▸Artesian conditions across much of its extent
- ▸Water quality generally excellent due to sandstone filtration
- ▸Long-term drawdown in high-use areas
States Overlying the Cambrian-Ordovician Aquifer System
Explore Water Assets Over the Cambrian-Ordovician Aquifer System
See every tracked spring, well, and water right that draws from this aquifer on our interactive map.
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