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Combined Sewer Overflows (CSO)
Sign up to receive notifications of combined sewer overflows
While we work to minimize CSO’s as much as we possibly can with current funding, we understand that notification of when we discharge is important to many downstream communities and other watershed users. Sign up now to receive notification when a CSO discharge occurs. We will notify you within two hours of the start of a discharge and update every eight hours.
Want to know more about how we work to reduce CSO events? Check out our High Flow Management page for a detailed review or contact a member of the Lowell Regional Wastewater Utility.
Recent Overflow Notification
This is a public notification that discharges of blended wastewater and/or untreated Combined Sewer Overflows (CSOs) were active at the Lowell Wastewater Utility and/or its diversion structures on 12/29/25 starting at approximately 12/29/25 11:58 am. These overflows ceased at approximately 12/29/25 6:29 pm.
It is recommended to avoid contact with these water bodies for 48 hours after the discharge or overflow ceases due to increased health risks from bacteria and other pollutants. A follow-up email will be distributed when these discharges have ceased.
Blended Wastewater
| Outfall ID | Location | Latitude | Longitude | Receiving Water | Average Discharge Volume (MG) | Discharge Start Time |
|---|---|---|---|---|---|---|
| 035 | LRWWU | 42.6452 | -71.28881 | Merrimack River | 11.60 | 12/29/25 11:58 am |
Combined Sewer Overflow Outfalls
| Outfall ID | Name | Latitude | Longitude | Receiving Water | Average Discharge Volume (MG) | Discharge Start Time |
|---|---|---|---|---|---|---|
| 002-SDS#1 | Walker Station | 42.6462 | -71.3341 | Merrimack River | 1.88 | No Diversion |
| 007-SDS#2 | Beaver Brook | 42.6593 | -71.3193 | Beaver Brook | 1.21 | No Diversion |
| 008-SDS#3 | West Station | 42.6525 | -71.3103 | Merrimack River | 5.95 | No Diversion |
| 011-SDS#4 | Read Station | 42.6482 | -71.3011 | Merrimack River | 0.06 | No Diversion |
| 012-SDS#5 | First Street | 42.6476 | -71.2909 | Merrimack River | 0 | No Diversion |
| 020-SDS#6 | Warren Station | 42.6428 | -71.3050 | Concord River | 3.53 | No Diversion |
| 027-SDS#7 | Tilden Station | 42.6507 | -71.3115 | Merrimack River | 1.01 | No Diversion |
| 030(1)-SDS#8 | Barasford Station | 42.6452 | -71.2884 | Merrimack River | 5.04 | No Diversion |
| 030(2) | Merrimack Station | 42.6452 | -71.2888 | Merrimack River | 5.69 | No Diversion |
Data
See below for data on high flow management
CSO Report 2020
CSO Report 2021
CSO Report 2022
CSO Report 2023
CSO Report 2024
CSO Report 2025
SSO Reports 2023
SSO Reports 2024
High Flow Summary Report 2020
High Flow Summary Report 2021
High Flow Summary Report 2022
High Flow Summary Report 2023
To view MassDEP Sewerage Notification Public Portal click here