Online Water Quality Monitoring (OWQM) uses online instruments for real-time measurement of water quality in source waters and/or distribution systems. OWQM can help utilities optimize treatment processes, improve distribution system operations, and detect contamination incidents. The resources on this page can be used to design and implement an OWQM system.You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.
Online Source Water Quality Monitoring for SRSs (PDF)(114 pp, 15 MB)
Guidance document that covers the design of real-time source water quality monitoring systems that can be used to optimize treatment processes, detect source water contamination incidents, and monitor threats to long-term source water quality.
Online Water Quality Monitoring in Distribution Systems (PDF)(86 pp, 8 MB)
Guidance document that covers the design of real-time distribution system water quality monitoring systems that can be used to monitor for contamination incidents and more common water quality incidents (e.g., nitrification), as well as provide greater operational control in distribution systems.
Guidance for Building Online Water Quality Monitoring Stations (PDF)(37 pp, 4 MB)
Guidance document that covers the design, fabrication, and installation of monitoring stations for a wide range of installation sites in a utility’s source waters and distribution system.
Guidance for Designing Communications Systems for Water Quality Surveillance and Response Systems (PDF)(69 pp, 3 MB)
Guidance document that covers the design of communications systems used to transmit data from remote monitoring locations to a control center.
Exploratory Analysis of Time-series Water Quality Data (PDF)(36 pp, 2 MB)
Guidance document that describes how to methodically characterize normal water quality variability and identify the factors that can impact data at individual monitoring locations.
Distribution System Water Quality Monitoring: Sensor Technology Evaluation Methodology and Results (PDF)(60 pp, 1 MB)
Report that provides a summary of the ability of various online water quality instruments to detect a wide range of contaminants. It also describes the operation and maintenance requirements of each instrument.
Water Quality Event Detection System Challenge: Methodology and Findings (PDF)(98 pp, 6 MB)
Report that summarizes results from an evaluation of a number of anomaly detection systems. The evaluation focused on the ability of the systems to both detect true water quality anomalies and minimize the rate of invalid alerts.