Bettendorf and Davenport would agree to make an estimated $160 million in sewer system upgrades over the next 20 years under a proposed consent order with the Iowa Department of Natural Resources (IDNR).
The agreement, currently under review by both cities, would address so-called sewage "bypass" flows at the Davenport treatment plant, which is one-quarter owned by Bettendorf.
During periods of heavy rain, water infiltrates sewer lines, creating flows which the plant can't handle and resulting in the dumping of partially treated sewage into the Mississippi River.