The Continuous Environmental Monitoring Program (CEMP) monitors real-time water quality conditions throughout the Sacramento-San Joaquin Delta (the Delta) and Suisun Bay. Data is transmitted to the California Data Exchange Center (CDEC) via wireless telemetry in real-time, providing pubicly available enviornmental data related to the Delta and Suisun Bay. Real- time data is continously collected at 15-minute intervals at 15 stations throughout the Delta and Suisun Bay. YSI EXO sondes are used as standalone water quality instruments at each station. The water quality data collected by CEMP guides the operations of the California State Water Project to maintain mandated water quality standards within the Delta and Suisuin Bay. Water quality standards are established for DWR by Water Right Decision 1641. All 15 of CEMP’s continuous water quality stations are included in this dataset for the calendar year of 2021. CEMP has collected water quality data in the Sacramento- San Joaquin Delta and Suisun Bay since the mid-1980s. Over the past 4 decades, CEMP’s monitoring scope has continuously increased in the number of monitoring locations and the amount of water quality analytes monitored. CEMP has strove to deploy the most up to date water quality monitoring technology at all of its monitoring stations. Currently, there are 15 water quality stations maintained by CEMP. All water quality monitoring stations collect data every 15 minutes, 365 days a year and are sent in real-time via telemetry. Core Tenants of CEMP: • to obtain consistent and accurate data in real-time at established monitoring stations • to provide data necessary to achieve compliance with salinity, flow, and dissolved oxygen standards • to perform data analyses for further understanding of estuarine ecology • to report information to other government agencies, as well as the public, for the purpose of management and conservation of the upper San Francisco Estuary (SFE). • to provide continuous water quality monitoring expertise for other groups within DWR and sister agencies for the benefit of ecological studies throughout the San Francisco- Sacramento Estuary