The analysis of return flows in a cascade of tank system envisages at quantifying the contributions of upstream to downstream tanks owing to cascade effect. The water balance study of a typical cascade system of four tanks under semi-arid climatic conditions in South India provided basis for estimation of return flow. On receipt of return flow from the immediate upstream tank (Devanpalli) and at the same time, in the process of contributing its portion of inflow as return flow to immediate downstream tank (Yergeri), the Tuntapur tank system found to gain a net area in the range of 62.5 to 39.59 ha. Similarly, Yergeri and Gunjalli tanks gained the catchment in the range of 31.75 to 7.59 ha and 29.4 to 11.11 ha respectively. The Devanpalli tank found to contribute a net area in the range of 102.64 to 119.03 ha.