The Metropolitan St. Louis Sewer District (MS D), the nation’s fourth largest sewer system by miles of pipe, has agreed to continue making improvements to its sewer systems and treatment plants at an estimated cost of $4.7 billion over 23 years, to eliminate flows of untreated sewage and to reduce pollution levels in urban rivers and streams, and, ultimately, the Mississippi River. United States v. Metro. St. Louis Sewer Dist., No. 07-1120 (E.D. Mo. Proposed consent decree lodged 8/4/11).

Under the proposed consent decree, MS D will invest $100 million in a green infrastructure program that will store, infiltrate and evaporate storm water to prevent it from getting into the combined sewer system. The utility will also spend $230 million in a flood mitigation program focused on disadvantaged areas and $1.6 million on a voluntary program to help low-income property owners connect septic tanks to the public sewer system and rehabilitate private laterals to reduce inflow and infiltration. MS D will pay a civil penalty of $1.2 million. The proposed consent decree is subject to public comment and judicial approval.