PSA has promoted water and basic sanitation since its founding in 1987. The water treatment and supply systems in Western Pará, like other programs, are based on:

• Technological innovation – hybrid systems, powered by solar energy and diesel, supplying entire communities at an affordable cost to the population.
• Decentralization – in the model developed by PSA, each community has its own water supply and distribution system. PSA maps the needs of the community and designs a custom-made project.
• Community participation – the systems are implemented with the help of the communities themselves, who work collaboratively. Along with its partners, PSA purchases the necessary materials and equipment and guides residents during construction.
• Self-management – during implementation, residents receive training and learn about the system in depth, allowing them to manage it themselves. Throughout the implementation process and with the support of PSA, each community creates its own water-use regulations and democratically elects the management board, which oversees the network in a transparent and sustainable manner.