Climate change will affect water supplies in south Asia, where high-intensity floods and droughts are expected in the future. Increasing water storage is a key adaptation strategy, and the experience of irrigation tanks illustrates both the potential and challenges of this adaptation response. Although there are over 2,08,000 tanks in India, irrigating about 2.3 million hectares in 2000-01, the net area irrigated by tanks declined by 29% between 1990-91 and 2000-01 and by 32% between 2001 and 2008. This paper reviews the challenges faced by tank irrigation and examines options for improving their performance – revenue mobilisation through multiple use of tanks, augmenting groundwater resources in the tanks, integrating social forestry and desilting, and tank modernisation.