combined sewer overflows | Michigan Radio
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combined sewer overflows

A bridge over a murky river has a drain with bars across it.
Lester Graham / Michigan Radio

From January 2018 through May 2019, 6.7 billion gallons of diluted or partially treated sewage, called combined sewer overflows (CSOs) spilled into Michigan waters.

CSOs are the result of sewer systems that drain both stormwater runoff AND human and industrial waste. Eighty municipalities in Michigan have such systems, known as combined sewer systems.