This chapter focuses on the results of a study of tanks in Ramanathapuram District, Tamil Nadu. This district has over one-fourth of the Tamil Nadu tanks and 75 percent of the state's 10,000 Ex-zamin tanks. In contrast, a number of rehabilitation alternatives can be implemented fairly quickly in a limited number of tanks. A large variation in farm size, strong private groups of well owners, and encroachment in the tank foreshore are factors which are likely to make rehabilitation difficult and unproductive. To develop a criteria for selecting tanks to rehabilitate the first step is to identify which factors influence tank performance. Little effort has been made to study the feasibility of using tanks as an alternative for expanding the irrigated area and production. Most of the explanatory variables were statistically significant and the coefficients were relatively high for tank and well water. The magnitude of the variables influencing tank performance varies from tank to tank.