The Department of Environmental Quality released its 2007 Combined Sewer Overflow (CSO) & Sanitary Sewer Overflow (SSO) Annual Report today which outlines the latest annual release information along with a special feature providing the history of how Michigan became a national leader in CSO control.

CSOs are overflows from older sewer systems designed to carry both domestic and storm water loads, while SSOs are discharges of raw or inadequately treated sewage from municipal separate sanitary sewer systems, which are designed to carry domestic sanitary sewage but not storm water. Discharges of untreated sewage can cause serious detriment to area water quality and often pose significant health risks to the public. Through extensive state support and a strong commitment from communities across Michigan, the state has made steady progress in eliminating discharges of SSOs and untreated CSOs.

In 1988, before any state-wide comprehensive CSO controls were in place, more than 600 untreated outfalls poured billions of gallons of harmful wastewater into local waters. Today, more than 75 percent of those untreated CSO outfalls have been eliminated by either sewer separation or by providing retention and treatment prior to discharge. Efforts are underway to address the remaining untreated CSO outfalls.

"These improvements mark continued progress towards eliminating threats to our waters and the health of our families from the discharge of untreated sewage," said DEQ Director Steven E. Chester. "We must continue to make the necessary financial and resource investments in Michigan's future until all untreated sewer overflows are eliminated."

In 1989, the combined efforts of governmental agencies at the local, state, and federal levels created the State Revolving Fund which has tendered more than $2.8 billion in low-interest loans to communities throughout the state for the necessary infrastructure improvements, including CSO and SSO correction projects that are protecting the health and safety of Michigan's residents.

Over the next 10 years, continued construction and implementation of ongoing CSO control efforts is expected to cost an estimated $2.875 billion.

The 2007 CSO & SSO Annual Report is available online at: http://www.michigan.gov/documents/deq/deq-wb-csossoreport07_243725_7.pdf.

Editor's note: DEQ news releases are available on the department's Internet home page at www.michigan.gov/deq.

"Protecting Michigan's Environment, Ensuring Michigan's Future"

Revised July 31, 2008 by Pat Watson