From Ocean to Tap: ABAQUA’s Role in Supplying and Desalinating Water for the Islands

On islands surrounded by the sea yet lacking in fresh water, water management becomes a matter of survival. Rainfall is irregular, aquifers are under strain, and tourism drives up demand every summer. It was against this backdrop that ABAQUA, the Balearic Water Agency, was set up. This public body is responsible for planning, building and managing essential water infrastructure, ranging from large-scale desalination plants to reservoirs that supply the local area. Its work is quiet yet crucial: ensuring that, despite population growth or periods of severe drought, the tap keeps running and water always meets the highest quality standards.

Behind every glass of water lies an unseen journey. This journey begins at two different points: the ocean and aquifers. Seawater desalination plants (SDPs) use reverse osmosis to process seawater. First, any sand and impurities are filtered out; then, pressure is used to separate salt from the fresh water using special membranes. It’s then treated to comply with drinking water standards before being stored in large tanks. The leftover salty brine then undergoes controlled discharge back into the sea, using systems that ensure it is properly diluted and cause no environmental impact.

ABAQUA’s plants have seen major improvements in recent years. They feature energy recovery systems that harness pressure generated in the desalination process to reduce electricity consumption. They also use sensors and remote-control technology to monitor everything that happens within the facilities in real time. In times of climate change and the energy transition, efficiency is just as important as quantity.

Management is equally strict on land. Aquifers remain a vital source, but only the amount of water actually needed is extracted. ABAQUA monitors groundwater levels and regulates their use: as well water replenishes, extraction is scaled back; as reserves decline, desalinated water is introduced. This prevents overexploitation and protects the natural balance. In Mallorca, for example, water supplies from Sa Costera and s’Estremera are supplemented by water from three desalination plants in Palma, Alcúdia and Andratx. The system is adjusted depending on the time of year.

Once treated, the water flows through a network of pipes and pumping stations spanning the islands. ABAQUA supplies water in bulk, delivering it to large municipal reservoirs. From there, local councils distribute the supply to households. This flexible system means water flows can be redistributed in periods of peak demand or at times of drought. For example, Ibiza ensures a stable water supply network by connecting its three desalination plants; Formentera gets its entire water supply from the sea; and Menorca reinforces its water security through the plant in Ciutadella.

Careful planning is key. Since its creation in 2005, ABAQUA has taken a holistic approach to the water cycle, in which water supply, sanitation and wastewater treatment are all part of the same strategy. Every decision counts: from when to start pumping, to planning downtime for maintenance. The EU Water Framework Directive provides the framework for protecting ecosystems, using resources responsibly and ensuring transparent management.

Quality control is an ongoing process. Every plant and reservoir is equipped with systems that analyse the water on a daily basis and adjust disinfection levels. A pump failure or change in chloride levels triggers automatic alerts and mobilises maintenance teams. Everything is monitored. This technical precision, though not immediately obvious, is crucial to ensuring that the water always has the same taste and quality, whether in January or in the height of August.

The coastline is also a focus of sustainability. In summer, a fleet of boats cleans the coastline to remove floating debris. Keeping the coastline clean protects water intake points and brine outfalls, while improving the image of a destination closely tied to the sea. Caring for the environment is not an afterthought, but a core part of the cycle.

ABAQUA is also looking to the future. It’s developing digital tools for smarter system management and implementing circular economy projects to reduce the islands’ energy footprint. The reuse of treated water, rainwater harvesting and integration of renewable energy into the plants are the next big goals.

The result is a model that is constantly evolving. When the islands hit peak tourist numbers, the desalination plants ramp up their output; when it rains and aquifers replenish, the system slows down. Ibiza has managed to curb the salinisation of well water, Formentera no longer relies on its aquifer, and Mallorca can guarantee a water supply even throughout the driest summers.