New Bedford CSO Discharge Table

CSO Discharge Table

  • The City's owns and operates a combined sewer system that dates to the late 1800's and early 1900's. When constructed, it was common practices to convey both street runoff and sanitary flow in a single pipe - hence the term "combined" sewer system. A combined sewer overflow (CSO) occurs when a large rain event overwhelms the sewage system and the combined rainwater and wastewater discharges to a nearby water body. Although this is not ideal to have untreated sewage being discharged during these extreme rain events, it does prevent sewage backups into homes and businesses. The City of New Bedford manages 27 CSO outfalls and is constantly monitoring and improving the wastewater system to minimize the number of discharges that occur during rain events.
  • When a CSO does occur, the City updates this public notification table within 2 hours but no more than 24 hours of a known overflow. Please be aware that sensor issues may occur and the City will correct faulty readings as soon as they are noticed.
  • The overflows listed above are best available estimates that are calculated from 3 sources - water level sensors that are installed in the city's smart sewer system, results from a calibrated hydraulic model that simulates flows and water level in the wastewater system, and statistical analysis of historical overflows. It is important to note that the overflows listed are estimates and should not be considered as exact values. The City of New Bedford assumes no responsibility or liability for any 3rd party uses of this data for analysis, calculations, or any other uses.