The planet is warming, and many scientists agree that the rise in temperature is human-made. However, science has not developed a model to predict the effects of increasing temperatures. Still, water utilities can and must plan for the uncertainties of climate change and its effects on water supplies and operations. The findings of a comprehensive case study, conducted by the East Bay Municipal Utility District in California on strategies to mitigate and adapt to climate changes, are presented in this article. Water utilities must include climate change in water supply availability and resource planning and can use this case study as a framework. The information presented in this article is applicable to long-term water supply planning and can assist with decision-making.