The Noyyal sub-basin, which is 3510 sq km in area, is part of the Cauvery basin that lies in the state of Tamil Nadu. It is a rapidly urbanizing sub-basin that includes the Class I cities of Coimbatore and Tiruppur as well as 84 smaller urban settlements. Water issues in this basin have been the focus of much public debate and action over the last two decades. Most of the debate, triggered by farmer agitations and court cases, has focused on the question of water pollution; water scarcity and sustainability issues have received relatively little attention. Recent bans on industrial effluent discharge into the Noyyal, as well as changes in water supply infrastructure, watershed development activities, urban demand and agricultural water use have dramatically altered the future of the Noyyal River and merit follow-up studies. The purpose of this situation analysis is to summarize the current state of knowledge regarding water resources management in the Noyyal sub-basin and identify critical knowledge gaps to inform water-related research in the basin. It is hoped that such an analysis will help those studying or working on water issues in the Noyyal, and also provide useful insights for other urbanizing basins.