The Metropolitan Water Reclamation District did an about-face Tuesday afternoon and voted to support disinfecting the 1.2 billion gallons of partially treated sewage it pumps into the Chicago River each day.

The 8-1 vote ends years of opposing the move as too expensive. Only district president Terry O’Brien voted no, arguing the district lacked the resources and that other priorities should be considered first. District staff told board members that disinfecting wastewater at all three of the district’s treatment plants would cost about $600 million. Excluding the biggest plant in Cicero would cut that figure approximately in half. 

Since 1972, the Chicago River and its tributaries have been exempt from the federal government’s Clean Water Act.  As a result, Chicago has pumped partially treated sewage into the river for years, making it the only major U.S. city to do so without killing the germs first. Last month, the U.S. Environmental Protection Agency issued an order requiring the district to clean up wastewater to the point where the Chicago River would be safe for swimming. 

Tuesday’s vote overturns the district’s formal opposition to the enhanced treatment and paves the way for purchase of new equipment that will remove disease-causing bacteria before it enters the waterway.