MSD Combined Sewer Overflow Reductions

The following graph demonstrates CSO reductions since MSD’s beginning in 1954. In the 1950’s, over 80 billion gallons of untreated wastewater from combined sewers flowed into St. Louis’ waterways. As noted from the table, CSO control projects have helped to greatly reduce the amount of untreated wastewater entering the Mississippi River and River Des Peres. From 1992 to 2006, when MSD began projects to address the nine minimum controls with an investment of $0.5 billion, combined sewer overflows have reduced by 33%.