Integrated water resources management approaches have been developed worldwide to improve water resources management practices. There are however, lingering issues with reference to the applicability of its integrated principles, especially when shifting from policy to practice (action). By conducting an exploratory case study in the Sao Paulo State, Brazil, this paper explores different stakeholders' perspectives regarding the water policy (Water Act of 1991). Through analysing institutional and water governance arrangements, the research assesses if current water policy is being translated into practice. Analysis suggests that the water policy and proposed principles are aligned with international approaches for water resources management. However, results also indicate that the principles by themselves are not sufficient to guarantee successful practice of a decentralised, participatory and integrated water resources management system. In a complex water management system, such as the one in the Sao Paulo State, coordination among different government levels and sectors is considered to be a key element to improve the likelihood of water policy implementation.