Report SSOs A Sanitary Sewer Overflow is an unintentional discharge of untreated sewage into the environment or onto property. If you encounter a sewer overflow, call BWSC 24 Hour Emergency Service Line 617-989-7000. BOSTON SEWER WE ARE ALL CONNECTED Let's Protect Boston's Waterways Boston Water and Sewer Commission BWSC.ORG Report SSOs A Sanitary Sewer Overflow is an unintentional discharge of untreated sewage into the environment or onto property . If you encounter a sewer overflow , call BWSC 24 Hour Emergency Service Line 617-989-7000 . BOSTON SEWER WE ARE ALL CONNECTED Let's Protect Boston's Waterways Boston Water and Sewer Commission BWSC.ORG