Water quality refers to the physical, chemical, and biological characteristics of water that determine its suitability for supporting ecosystems and human use. In aquatic ecosystems, maintaining good water quality is crucial for sustaining aquatic life, preserving biodiversity, and ensuring safe water for drinking, recreation, and agricultural purposes. Human activities have led to significant water quality issues in many parts of Australia, including algal blooms, nutrient pollution, and low oxygen. We have completed work examining water quality issues in marine (Glamore et al. 2018, Hitchcock et al. 2021b, Ruprecht et al. 2022) and freshwater ecosystems (Mitrovic et al. 2010, Facey et al. 2022), have developed new frameworks assessing water quality issues across the Murray-Darling Basin (Hitchcock 2015, Hitchcock and Evans 2016), and work closely with water agencies and government departments to develop solutions to water quality problems.