This essay looks at climate change impacts on small island developing states (SIDS). It argues that climate change adaptation and mitigation strategies must be developed to cope with changes such as shifting precipitation patterns, increasing evapotranspiration and expanding saline intrusion into coastal aquifers and wells. Using Jamaica as a case study, the paper examines the utility of rainwater harvesting (RWH) in SIDS and answers questions regarding: 1) how much rainwater can be harvested on the island given present and future precipitation patterns; and 2) how much can RWH realistically curb water supply deficits now and in the future. Water resources are also directly linked to many other considerations, including infrastructure, energy, agriculture and the overall economy. The study hopes to stimulate broader reflections on what concrete actions SIDS should take to prepare for the water resource impacts of climate change.