We know climate change is happening and we know stormwater and wastewater systems are vulnerable. What we don’t know is how these impacts will unfold over varying places and times. This discussion paper provides an overview of our current knowledge, and outlines priority research areas to help adapt our stormwater and wastewater systems for a changing climate. The paper draws on a range of expert input, including academia and Crown Research Institutes, the public and private sectors, and specifically water service providers and consultants. Research priorities are: to understand direct and indirect impacts, to identify adaptation opportunities within redevelopment and retrofit, to explore solutions to reduce dependence on legacy delivery mechanisms, and to identify potential improvements in stormwater risk management.