Climate change, water resources and sustainable development are intrinsically linked and critical to the future well-being of people and the environment. This chapter explains how managers are developing more secure water infrastructure and water resource plans, despite deep uncertainty about future climate, water supplies and demand. Our focus is on ways of developing climate-adjusted infrastructure (projects) and climate resilient water systems (plans). We begin with a synopsis of modelling frameworks for evaluating hydrological change. This is followed by a critique of techniques for incorporating allowances for climate change within detailed engineering designs. We then show how water system resilience to credible ‘storylines’ of change and climate extremes can be considered. Along the way, we identify key knowledge gaps and opportunities for improving water security despite uncertainty about climate change. These include improving access and availability of information about hydroclimate extremes, especially in data sparse regions; developing guidance and incorporating climate adjustments in asset design; and helping practitioners with the selection and application of plausible storylines for stress-testing water resource plans. More research is also needed into potentially abrupt hydrological shifts under climate change, with associated impacts on water quality, and environmental flow requirements.