Susquehanna River Basin's Early Warning System

The Commission designed the Early Warning System (EWS) to help protect the Basin’s drinking water supply. Safe drinking water is a basic need for everyone and the first step towards safe drinking water is to have a clean source of water. The EWS provides a framework for innovative partnerships and protocols and for fostering communication and data sharing among public water suppliers, state/local agency personnel, and the emergency response community for the purpose of enhancing drinking water protection efforts.

The current EWS enhances protections for public drinking water supplies serving about 850,000 people, provides a monitoring network that helps minimize the impact from contaminant spills, and provides data for improving day-to-day treatment operations, further ensuring a continuous and safe supply of drinking water. Furthermore, with heightened national security concerns, the Commission’s EWS has become an important tool for participating water suppliers and emergency management officials.

The EWS was established for Pennsylvanian water suppliers with intakes in the Susquehanna River in 2003 and was expanded into the New York portion of the Basin in 2006. The goal of the system is to monitor the river for changes in water chemistry and the presence of contaminates. The system consists of nine stations that monitor a minimum of pH, turbidity, and temperature. Four of the nine stations have enhanced monitoring for organic carbon contamination. Several of the stations also monitor for conductance and/or dissolved oxygen. The data collected by the nine stations help to minimize the effect of contamination events and improve day-to-day treatment operations.

For more information, please see the following links:


EWS partners include Chester Water Authority, Columbia Water Company, United Water of Pennsylvania, PA American Water Company, Danville Borough Water Department, Elmira Water Board, Binghamton Water and Sewer Department, Kirkwood Water and Sewer Department, U.S. Environmental Protection Agency, Pennsylvania Department of Environmental Protection, and Susquehanna River Heartland Coalition for Environmental Studies.

Data Disclaimer

Uncertainty and potential for error can be associated with environmental monitoring data. No warranty, express or implied, is given as to the accuracy, reliability, utility or completeness of the data hosted on this website, and the Commission shall not be held liable for improper or incorrect use of the data described or information contained on these pages.

Monitoring Parameters

Example of Early Warning System raw data