Using non‐parametric methods, we estimate the foregone rents due to credit, allocative, and technical inefficiencies of subsistence farmers in Southern India. The lost rents are estimated directly from the Nerlovian efficiency index, and the results suggest the largest foregone rents derive from allocative inefficiencies and then credit inefficiencies. Also, results suggest that farms without well access experience larger losses than those with well access. Econometric results suggest education, the presence of tank water management efforts, and well access influence the level of foregone rent due to allocative and Nerlovian inefficiencies. Educational activities and policies to encourage better management of tanks are considered important for lowering the foregone losses.