Growing competition over water resources has caused political disputes among stakeholders and has brought conflict resolution in the focus of negotiation processes. In these cases, bankruptcy rules for redistributing an asset when it is not sufficient to meet all claims could be applied. In this paper, we develop a new bankruptcy rule for water resources problems that considers agents' contribution to the total resources as well as their claims, which is in accordance with the UN Watercourses Convention (1997), as important factors for reallocation. Using the Euphrates River and a hypothetical case from the literature as examples, the new rule is compared with four alternative rules. The results show that the novel solution is potentially more powerful to help solving conflicts over river sharing problems.