MWRA has recently completed the final construction milestone of its Long Term Combined Sewer Overflow (CSO) Control Plan, a 25-year plan to reduce the impact of combined sewer overflows to surface waters in the metropolitan Boston area. The plan comprised 35 wastewater system improvement projects that bring CSO discharges at CSO outfalls in the Boston area into compliance with the Federal Clean Water Act.
What is a CSO?
CSO Annual Discharge Estimates and Rainfall Analyses Reports (2014-present)
CSO Annual Progress Reports (2004-2015)
CSO receiving water quality monitoring in Boston Harbor
A Sanitary Sewer Overflow (SSO) is an unintentional discharge of wastewater to the environment prior to reaching a treatment facility. SSOs occur on infrequent occasions when the capacity of the sewer system is exceeded, usually due to extreme conditions such as heavy rainfall, or an obstruction or break in sewer lines. MWRA SSO Notifications.
More about SSOs and how to help prevent them