The Jordan Aquifer is an important source of water for central Iowa, and CIWW already uses it as part of our water supply. However, it cannot meet the region’s long-term needs on its own.
Unlike rivers and shallow groundwater sources that are regularly replenished by rainfall, the Jordan Aquifer is a deep groundwater source located approximately 2,500 feet below central Iowa. Much of the water entering the aquifer comes from hundreds of miles away in northwestern Iowa and southern Minnesota and can take thousands of years to reach central Iowa. This means water comes out of the aquifer much more quickly than it goes back in. Because of this, the Jordan Aquifer is often referred to as a “fossil water” source.
Groundwater levels in the Jordan Aquifer have been declining for decades as more water has been withdrawn than naturally replaced. State studies dating back to the 1970s documented significant water level declines, leading Iowa to establish regulations to protect the aquifer from overuse. Those regulations have since been updated as water levels continued to drop.
Today, water levels in the Jordan Aquifer are still declining in central Iowa. If CIWW attempted to replace its river supplies with large-scale withdrawals from the aquifer, groundwater levels would decline much more rapidly, potentially affecting water quality, well performance, and the availability of the resource for future generations.
That is why CIWW uses a balanced approach. Our water supply comes from multiple sources that include rivers, reservoirs, and groundwater sources such as the Jordan Aquifer. Using a variety of water sources helps protect each resource, improves reliability, and ensures we can continue providing safe drinking water to central Iowa today and into the future.
You can learn more about the Jordan Aquifer and the Iowa Department of Natural Resources’ role in protecting this valuable resource here:
https://ciww.gov/wp-content/uploads/2026/06/JordanAquiferStakeholderReport202095.pdf