Project Clean Lake: Updating Cleveland’s Sewer Systems to Reduce Stormwater Overflows

Kirsten Feifel
Posted on: 4/23/2013 - Updated on: 3/02/2020

Posted by

Rachel Gregg

Project Summary

The Northeast Ohio Regional Sewer District created Project Clean Lake to reduce combined sewer outflow discharge to less than 98% by 2035. The project was formed after the Environmental Protection Agency (EPA) determined that the sewer district’s discharge rates into Lake Erie were in violation of the Clean Water Act. The project includes a combination of updates to existing infrastructure and the development of green infrastructure to help capture and retain stormwater flow. Climate change is expected to cause an increase in intense precipitation; this project will help to reduce the negative impacts climate change may pose to the city.


The Northeast Ohio Regional Sewer District (District) serves more than one million people residing in the greater Cleveland metropolitan area. Three wastewater plants – Easterly, Southerly and Westerly – coupled with over 200 miles of sewer pipes, transport and process over 90 billion gallons of wastewater annually. Roughly 80 square miles of the Cleveland sewer system were designed and built in the late nineteenth century and are commonly referred to as “combined sewers,” where a single pipe carries sewage, industrial waste, and stormwater. During periods of heavy rainfall, urban stormwater runoff can increase greatly, filling and overwhelming the combined sewer pipes. To prevent urban flooding, the Cleveland sewer system has control devices that allow some of the flow to be diverted into regional waterways such as Lake Erie. The District has 126 permitted combined sewer outfalls, where overflow during periods of heavy rainfall may discharge directly into waterways in the greater Cleveland area.   

The EPA found the District in violation of the Clean Water Act due to the periodic overflow of untreated wastewater into Lake Erie. In July 2011, the EPA and District filed a Consent Decree specifying new measurements the District would employ to reduce wastewater overflow over the subsequent 25 years.

Among other impacts, climate change is expected to increase extreme weather, including heavy downpours, in the Great Lakes region. The retrofitting improvements to the District’s sewer system will reduce the negative impacts that more frequent and intense rainstorms may cause to the Cleveland area.


Through Project Clean Lake, the District plans to reduce combined sewer overflow by 98% by 2035. The project has an estimated budget of $3 billion and will be one of the largest infrastructure projects ever to be completed in Cleveland. Funds for the project will be obtained from the District’s customers, who will experience yearly average increases of 13% from 2012-2016.

Initially, the District planned to upsize its “gray” infrastructure – pipes, overflow sites, treatment plants, etc. – for an estimated cost of $182 million. However, the District also considered a combination of upsized gray infrastructure coupled with the use of green infrastructure to capture and reduce stormwater flow. The District estimated that the inclusion of green infrastructure would actually save the city an estimated $87 million and achieve better combined sewer outflow capture results. 

The EPA approved the District’s plan to reduce combined sewer overflows in 2012. The plan includes the installation of seven major deep storage tunnel systems, high-rate wet-weather treatment facilities at all three of the wastewater treatment plants, and the use of green infrastructure to increase the area of permeable surfaces within greater Cleveland to help capture stormwater runoff. The green infrastructure will be designed to manage the flow on-site and will include a combination of rain catchments, permeable surfaces and parklands, and rain gardens. 

Outcomes and Conclusions

Project Clean Lake will create an estimated 31,000 jobs and generate $443 million in tax revenue. Its estimated completion date is 2035.


Feifel, K. M. (2012). Project Clean Lake: Updating Cleveland’s Sewer Systems to Reduce Stormwater Overflows [Case study on a project of the Northeast Ohio Regional Sewer District]. Product of EcoAdapt's State of Adaptation Program. Retrieved from CAKE:… (Last updated October 2012)

Project Contact

Affiliated Organizations

The District is responsible for wastewater treatment facilities and interceptor sewers in the greater Cleveland Metropolitan Area. This service area encompasses the City of Cleveland and all or portions of 61 suburban municipalities in Cuyahoga, Summit, Lake and Lorain Counties and includes a diversified group of manufacturing and processing industries.