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Metropolitan Water Reclamation District of Greater Chicago

About the Plant

  • 187 employees
  • 14 buildings on 97 acres
  • In operation since October 3, 1928 

Receiving Stream

  • North Shore Channel 

Treatment Volume

  • 230 million gallons/day (avg.)
  • 450 million gallons/day (max.)

O'Brien WRP Fact Sheet

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Tuesdays, 9 a.m.
2 hours
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The Terrence J. O’Brien Water Reclamation Plant (WRP) is one of seven wastewater treatment facilities owned and operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRD). The MWRD is the wastewater treatment and stormwater management agency for the City of Chicago and 125 Cook County communities. We work every day to mitigate flooding and convert wastewater into valuable resources like clean water, phosphorus, biosolids and natural gas. 

A tank full of brownish water with a brick tower building in the background

If you live within our service area, the water that goes down your toilet, sinks and drains eventually comes to us to be cleaned. We treat wastewater from homes and businesses throughout our 883-square-mile service area in addition to stormwater from some communities. All of this wastewater and stormwater flows through local sewers into our interceptors before flowing to WRPs where we clean the water and recover resources using a combination of physical, biological, and sometimes chemical, treatment processes.

The MWRD provides this service for over 5 million people. Nearly 450 billion gallons of wastewater is treated by our seven facilities every year.

The O’Brien WRP (originally called North Side) was built to serve residents in communities north of downtown Chicago. In operation since 1928, the O’Brien WRP originally treated sewage for a population of 800,000 within a 78-square-mile area, but now both the service area and the population are nearly twice as large. The O’Brien WRP currently serves over 1.3 million people in an area of 143 square miles and cleans an average of 230 million gallons of wastewater per day (mgd) and has the capacity to treat 450 mgd.