YSI is the leading provider of comprehensive water quality monitoring solutions for wastewater treatment systems. With over seven decades of innovation, YSI delivers field-proven instrumentation that helps wastewater utilities optimize treatment processes, ensure effective effluent quality, and maintain regulatory compliance.



From influent characterization to treatment plant optimization and effluent monitoring, YSI’s advanced sensor technology provides real-time data on critical parameters including dissolved oxygen, ammonia, nitrate, phosphorus, suspended solids, and more. Our IQ SensorNet network-based systems enable utilities to monitor up to 20 parameters simultaneously, ensuring optimal treatment efficiency and process control.



YSI’s scalable solutions range from handheld field instruments like the ProDSS for spot sampling to comprehensive online monitoring solutions for treatment facilities. Our field-tough, lab-smart instrumentation is backed by expert consulting and technical support services. Wastewater utilities worldwide trust YSI to deliver accurate, reliable data needed for efficient water quality management.