We use a framed-field experiment to analyze the preferences of Indian farmers regarding water sharing. Farmers play a dictator game (DG) behind the veil of ignorance in which a limited quantity of water has to be allocated between two farmers. We vary the equity/efficiency trade-off by introducing some heterogeneity between farmers' productivity and by considering an upstream/downstream spatial configuration. We first show that generosity in the DG is high (on average, respectively 44% and 47% of the total quantity of water or the total profit are left by the dictator). Only a small proportion of farmers act in the DG as selfish profit maximizers, a majority of them adopting efficient, egalitarian in payoff or egalitarian in quantity behaviors. We then show that it is possible to induce more efficient water allocation behaviors in the DG by modifying farmer's choice architecture. A loss framing induces farmers to share more efficiently the water resource, but only when the most productive farmer is located downstream. On the contrary, we find mild evidence that farmers choose less often the efficient solution with a gain framing.