MWRA is actively monitoring the situation in Minnesota and in other water systems across the country. MWRA has invested significantly in its security systems and protocols and our Operations and Security staff work around the clock to ensure that the water and wastewater systems are safe and secure. We have not discovered any of the vulnerabilities that are being exploited in other systems.
MWRA continues to work with state and federal partners, sharing information and best practices in order to protect the critical drinking water and wastewater systems that serve our customers.
Sanitary Sewer Overflow (SSO) Notifications
Subscribe to MWRA CSO, SSO, and Blending discharge notifications
A sanitary sewer is a system of underground pipes that carries sewage from homes and businesses to the wastewater treatment plant. If this sewer accidentally discharges wastewater to the environment before it's treated, that's a sanitary sewer overflow (SSO). They occur infrequently, and are often due to a break in the sewer line or heavy rain. Excess flow may be discharged to local water body without treatment, as a last resort to reduce the risk of sewage backups.
Public health officials recommend avoiding contact with water bodies during rainstorms and for 48 hours afterwards, as there may be increased health risks due to bacteria or other pollutants associated with urban stormwater runoff and SSO discharges. Because SSOs contain untreated sewage and waste, the Massachusetts Department of Environmental Protection requires MWRA to notify regulators and the public when an SSO occurs.
Click on individual markers on the map to view more detail. Additional information will appear in the popup window if multiple events occurred during the selected period. If there are no SSO events during the selected period, the map will display no markers.
SSOs displayed on the map have been reported to the Department of Environmental Protection by MWRA, this map does not include SSOs that may occur outside of the MWRA system.
*Information is preliminary and is subject to change.
SSO Map
Events active within the past two days appear as red markers
Older events are yellow
and bypass events are green
Additional discharge details
The SSO discharge data below provides additional details. Discharge duration and volume are estimates. Data are preliminary and subject to change.
***Partially treated discharge – unchlorinated treated wastewater was released to the South Branch Nashua River at the Clinton Treatment Plant outfall.
