Estuary water quality data has been collected by the Estuaries and Catchments Team of the Environment, Energy and Science Group in the Department of Planning, Industry and Environment since 2007. Data has been collected using a standard monitoring protocol outlined in 'Assessing estuary ecosystem health: Sampling, data analysis and reporting protocols. NSW Natural Resources Monitoring, Evaluation and Reporting Program', most recently updated in 2016 and available on the NSW environment website. The data has been used to monitor the aquatic ecosystem condition of over 160 estuaries in NSW over time. Adopting the principles of the National Water Quality Management Framework, the data has been used to develop NSW specific guideline values for a range of physico-chemical water quality indicators for each estuary type. This allows comparison of observed data to these guidelines to assess condition of any estuary in NSW. As part of the Marine Estate Management Strategy Implementation Plan Stage 1, a NSW water quality database has been developed, where this data is now stored. Water quality monitoring in NSW estuaries is ongoing, and updated data will be made available routinely.