City of Grand Rapids Combined Sewer Overflow (CSO) Project - Eliminating Sewer Overflows into the Grand River

In 2015 the City of Grand Rapids completed a Sewer Improvement project. This eliminated all Combined Sewer Overflow (CSO) points in the sewer system. The original, state-mandated deadline was 2019.

Combined sewer systems carry treated sewage and stormwater. Untreated sewage from older sewer systems can overflow into combined sewer systems. When these overflows happen, we call them Combined Sewer Overflows (CSOs).

When CSOs happen, the following discharge into the ground, our rivers, lakes or streams:

  • Untreated or partially treated human and industrial waste
  • Toxic materials
  • Debris
  • Disease-causing organisms
In the 1960s, Grand Rapids dumped as much as 12.6 billion gallons of raw sewage into the Grand River each year. This sparked a national controversy.

Construction on this $400 million project started in 1991. Ratepayers' utility bills will continue to finance the project until 2042. 

Today, we have a state-of-the-art wastewater treatment system. It eliminates 100% of sanitary sewer water pollutants from entering the river.

This project has had environmental, financial and social impacts in Grand Rapids.

  • 12.6 billion – Gallons of raw, untreated sewage flowing into the Grand River in 1969
  • 0 – Gallons of raw, untreated sewage flowing into the Grand River in 2014


Phone: 311 or 616-456-3000


Water Rescource Recovery Facility
1300 Market Ave SE
Grand Rapids
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This project improved water quality for all current and future residents and visitors. At times the construction work was an inconvenience to neighborhood routines and traffic. It was all worthwhile because it upgraded the outdated, 100 year-old system. We now have proper storm and sewage systems.

Green infrastructure improvements

During this project, the City also made other green infrastructure improvements. They have installed rain gardens (bioswales), porous pavement, and hydrodynamic separators to remove sediments. These improvements are decreasing water flows on concrete and asphalt surfaces.

The CSO problems are largely solved. Now the City is turning its attention to better managing stormwater runoff. Wastewater and stormwater infrastructure improvements can lead to a 1 - 5% increase in property values. Research commissioned by the City through Grand Valley State University estimated these figures.