New Zealand’s freshwater habitats including rivers, lakes, estuaries and other wetlands; groundwater and geothermal ecosystems support a unique array of flora and fauna. Freshwater is New Zealand’s greatest asset and is a taonga of paramount importance. It is valued for its contribution to biodiversity, recreation, the economy and overall well-being of New Zealanders. It is also a vital element of whakapapa and provides valuable resources such as mahinga kai (indigenous freshwater species that have traditionally been used as food, tools, or other resources), and underpins the country’s ever-growing tourism industry. Reinforcing this importance, New Zealanders consider water quality to be the most important environmental challenge facing New Zealand. This Conservation Science Statement uses the latest scientific understanding of New Zealand’s unique freshwater ecosystems (rivers, lakes, other wetlands, groundwater ecosystems) to propose how effective policy and management based on scientific evidence can safeguard their future for generations to come.