District and History

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) is an independent government and taxing body encompassing approximately 91% of the land area and 98% if the assessed valuation of Cook County, Illinois.

MWRD is a separate legal entity sharing an overlapping tax base with the City of Chicago, the Chicago Board of Education, the Chicago School Finance Authority, the County of Cook, the Cook County Forest Preserve District, the Chicago Park District, The Chicago Public Building Commissioner, The Cook County Community College District, and various municipalities and school districts outside the City of Chicago but within the MWRD’s boundaries.

The MWRD was originally organized as the Sanitary District of Chicago in 1889 under an act of the Illinois General Assembly which has been modified from time to time to increase the MWRD’s authority and jurisdiction. The enabling act in 1889 was in direct response to a long standing problem with contamination of the water supply and nuisance conditions of the rivers. The MWRD reversed the flow of the Chicago and Calumet River Systems to stop the discharge of sewage to Lake Michigan and instead, discharge it to the Des Plaines River, where it could be diluted as it flowed into the Illinois River and eventually the Mississippi River. Prior to the MWRD’s construction of a 61.3 mile system of canals and waterway improvements, the Chicago and Calumet River Systems were tributary to Lake Michigan. These river systems are now tributary to the Illinois River system.

From 1955 through 1988, the MWRD was called The Metropolitan Sanitary District of Greater Chicago. In order to provide a more accurate perception of the MWRD’s current functions and responsibilities, the name was changed effective, January 1, 1989, to Metropolitan Water Reclamation District of Greater Chicago.

Mission and Responsibilities

The mission of the MWRD is to protect the health and safety of the public in its service area, protect the quality of the water supply source (Lake Michigan), improve the quality of water in watercourses in its service area, protect business and homes from flood damages, and manage water as a vital resource for its service area.

The MWRD collects wastewater from municipalities in its service area, conveys it to wastewater reclamation plants, provides full secondary treatment and discharges clean water to local waterways. The MWRD is also responsible for stormwater management for all of Cook County, including areas outside of the MWRD’s corporate boundaries for wastewater services.


The MWRD’s seven modern water reclamation plants provide treatment for residential and industrial wastewater, meeting permit discharge limits virtually at all times. The treatment process is protected by a pretreatment program to guard against hazardous substances and toxic chemicals. These are strictly regulated pursuant to federal and state requirements. The MWRD routinely monitors all industries and nonresidential sources to assure that wastes are disposed of in an environmentally responsible manner.

Treated wastewater, along with runoff from rainfall, enters local canals, rivers and streams that serve as headwaters of the Illinois River system. Stormwater in the separate sewered area is controlled to reduce flood damages by a number of storm water detention reservoirs. In the combined sewer area, the MWRD’s tunnel and reservoir project has significantly reduced basement backup and overflows to local waterways.

Flow within the MWRD’s waterway system and the Lake Michigan discretionary diversion flow are controlled by three inlet structures on Lake Michigan: Wilmette Pumping Station, Chicago River Controlling Works and O’Brien Lock and Dam. The single outlet control structure is the Lockport Lock and Powerhouse.

While exercising no direct control over wastewater collection systems owned and maintained by cities, villages, sewer districts and utilities, the MWRD does control municipal sewer construction by permits outside the city of Chicago. It also owns a network of intercepting sewers to convey wastewater from the local collection systems to the water reclamation plants.

Rain Barrel Program
Order a Rain Barrel
Report Water Way Blockages
Report a Pollution Incident
Whistleblower Hotline
Stormwater Management
Biosolids Program


The MWRD is located primarily within the boundaries of Cook County, Illinois. The MWRD serves an area of 883.5 square miles which includes the City of Chicago and 125 suburban communities. The MWRD serves an equivalent population of 10.35 million people; 5.25 million real people, a commercial and industrial equivalent of 4.5 million people, and a combined sewer overflow equivalent of 4.5 million people, and a combined sewer over flow equivalent of 0.6 million people. The MWRD 554 miles of intercepting sewers and force mains range in size from 12 inches to 27 feet in diameter, and are fed by approximately 10,000 local sewer system connections.

The MWRD Tunnel and Reservoir Project (TARP) is one of the country’s largest public works projects for pollution and flood control. Four tunnel systems total 109.4 miles of tunnels, 9 to 33 feet in diameter and 150 to 300 feet underground. One reservoir is in operation and construction is in progress on the two remaining reservoirs.

The MWRD owns and operates one of the world’s largest water reclamation plants, in addition to six other plants and 23 pumping stations. The MWRD treats an average of 1.4 billion gallons of wastewater each day. The MWRD total wastewater treatment capacity is over 2.0 billion gallons per day.

The MWRD controls 76.1 miles of navigable waterways, which are part of the inland waterway system connecting the Great Lakes with the Gulf of Mexico. It also owns and operates 35 stormwater detention reservoirs to provide regional stormwater flood damage reduction.

In conjunction with its biosolids beneficial utilization and farm land application program, the MWRD recycles all biosolids in land application programs in northeast Illinois and owns over 13,5000 acres of land in Fulton County, Illinois, formerly used for biosolids application.

The MWRD is governed by a nine-member Board of Commissioners (Board). Commissioners are elected at large and serve on a salaried basis. Three Commissioners are elected every two years for six-year terms. Biannually, the Board elects from its membership a President, Vice president, and Chairman of the Committee on Finance.

The Executive Director, who reports directly to the Board, manages the MWRD’s day-to-day operations. Eight appointed department heads report to the Executive Director

The Treasurer of the District, its chief financial officer, is appointed by and reports directly to the Board.

General Administration, management & Budget, Affirmative Action, and Public Affairs are direct staff and support units, reporting to the Executive Director.