Israel's water crisis has accelerated the development of alternative water sources. Desalinated sea-water has been accepted as a suitable solution providing the required quantities. Its quality, however, arise major problems, having extremely low concentration of some minerals essential to both plants and humans. Attaining adequate mineral content can be achieved by blending high-mineral with low-mineral content water and/or by adding minerals at different locations in the distribution system. The work develops a management model to supports decision-making in Regional Water Distribution System (RWDS), when quality requirements are to be met. The decisions to be made are water source production and remineralization policy. Applying the model to a part of a RWDS resulted in remineralization policy that combined both blending and mineral addition. The key factors affecting the policy were the distribution system's layout and the different consumers' quality standards.