CSO Alert

When local sewage plants release untreated sewage into the Merrimack River, the Merrimack River Watershed Council provides alerts to the public. These alerts are sent to us by the treatment plants, and we post them as quickly as possible.

You can use these alerts to make decisions about your activities on the river. For example, during periods of major releases of sewage, you may want to limit your contact with river water for a period of 72 hours.