Combined Sewer Overflows (CSOs)
and CSO Notifications

Background

Combined Sewer Overflows (CSOs) captured the public’s attention in Fall of 2018, when above average rainfall resulted in the release of hundreds of millions of gallons of a mix of stormwater and partially treated sewage into the Merrimack River.  

Combined sewer systems were first introduced in the 1850s, and initially discharged sewage directly into water bodies. However, from the early part of the 20th century, wastewater treatment facilities were added to clean this discharge.

In an effort to educate the public and legislators about CSOs, the MCWRS has created this video to inform viewers on what CSOs are and how they can be reduced in the future:

An Act Promoting Awareness of Sewage Pollution in Public Waters

In January 2021, Chapter 322 of the Acts of 2020, An Act Promoting Awareness of Sewage Pollution in Public Waters was signed into law, and went into effect in July 2022. Of note is the requirement for permittees to issue public advisories for discharges of certain types of untreated or partially treated wastewater within two hours of discovery.

One unintended consequence of this legislation was the tracking of blended wastewater, a process that protects the biological activity of a treatment facility and in some cases allows for higher volumes of treatment. 

To make matters worse, language was required for notification alerts for both CSO and SSO reporting to warn about the dangers of recreation in waters within 48 hours of a CSO.  Lastly, the regulations promulgated by MassDEP as required by the Law require extensive reporting of CSOs and SSOs via an online portal.  Each event at each outfall must be reported separately – a very time consuming job.  Overall, this reporting has created unnecessary work for wastewater professionals when these flows are typically in compliance with permit limits.  Even with all the reporting since July 2022 -  no additional monies have been directed to CSO abatement in a meaningful way. 

MCWRS Advocacy and Resources

• MCWRS Comments on Proposed Regulation 314 CMR 16.00 Notification Requirements to Promote Public Awareness of Sewage Pollution (November 2021)

• MCWRS White Paper on CSO Notification (June 2019)

• Educational video on CSOs with Springfield Water and Sewer Commission (above)

In March 2021, we hosted a webinar discussing this issue in more depth. Members can access a recording of this webinar free of charge by contacting info@mcwrs.org.