Sewer overflows in Massachusetts
Sewer overflow record — reported spills, the worst utilities, and how often overflows reached waterways in Massachusetts.
Reported events
9
Total volume
16.1M gal
Reached waterways
0(0%)
Latest event
Mar 16, 2026
Worst utilities in Massachusetts
Ranked by number of reported overflow events.
| # | Utility | Events | Volume | Reached water |
|---|---|---|---|---|
| 1 | Amherst Sewer Collection System | 7 | 52K gal | 0 |
| 2 | MWRA - Deer Island Sewer Collection System | 2 | 16.1M gal | 0 |
Biggest spills in Massachusetts
The largest single reported overflow events.
- 10.1M galMar 16, 2026Reached Massachusetts Bay
- 6.0M galMar 16, 2026Reached Massachusetts Bay
- 46K galFeb 6, 2024
- 3K galJan 15, 2024
- 1K galJan 26, 2024
- 1K galJan 10, 2024
- 780 galMar 7, 2024
- 200 galMar 11, 2024
- 100 galNov 4, 2023