About MSD

The Metropolitan St. Louis Sewer District (MSD) was formed on February 9, 1954, when voters approved the Plan of the District. MSD started operation and maintenance activities in January 1956 in an area roughly compromised of the City of St. Louis and the portion of St. Louis County east of Interstate 270. Most of the remainder of St. Louis County was annexed by the District in 1977.
MSD is a public agency and is the only special district in Missouri created under a provision of the State Constitution.
MSD's responsibilities include the interception, collection and treatment of wastewater, as well as stormwater management.
The District's current boundaries cover 525 square miles and encompass all of the City of St. Louis and approximately 80% of St. Louis County.
MSD serves a population of approximately 1.4 million and has approximately 519,000 single-family residential, multi-family residential and commercial/industrial accounts. Of these accounts, approximately 87,000 are for stormwater service only.
MSD currently operates seven wastewater treatment facilities, treating a combined average of 330 million gallons of sewage per day.
The District is responsible for operating and maintaining 9,649 miles of sewers.
- 2,980 miles of stormwater sewers
- 4,741 miles of sanitary sewers
- 1,928 miles of combined sewers*
- *Combined sewers handle both wastewater and stormwater flows.
The age of sewers maintained by MSD ranges in age from less than a year old to 150 years old. MSD has 311 miles of sewers predating 1890, and another 524 miles of sewers more than 80 years old.