Costa del Sol revives long-delayed €50m mega-project to double core water supply capacity

The project aims to overhaul and double the treatment capacity of the El Verde drinking water treatment plant (Estación de Tratamiento de Agua Potable - ETAP) in Marbella.

Serving as the core "heart" of the region's water supply network, the El Verde plant currently operates under severe structural bottlenecks. Built in 1972, the facility has a theoretical design capacity of 2,300 litres per second, but obsolete equipment restricts actual throughput to barely 1,500 litres per second.

Under a new administrative agreement, Acosol has assumed full operational control of the project from the Andalusian regional Ministry of Agriculture, though the regional government will continue to provide primary funding for the initiative, which is estimated to cost well over €50 million.

Acosol has officially launched a public tender worth €692,000 (including IVA) for the preliminary engineering design, setting a nine-month execution timeframe.

The finalised expansion will increase the plant’s operating capacity to approximately 4,600 litres per second, creating a system capable of handling peak summer demand for a seasonal population ranging between 1.5 million and two million inhabitants.

"The water supply to the Costa del Sol relies on strategic infrastructure that is over half a century old," explained project engineers. "The modernisation will eliminate processing bottlenecks, enable maintenance closures without triggering production cuts, and ensure strict water quality standards."

In addition to expanding treatment lines, the project includes the total refurbishment and construction of twin headwater storage reservoirs. Divided into four isolated compartments, the dual facilities will feature a combined storage capacity of 120,000 cubic metres.

This volume represents approximately half a day’s consumption during peak summer periods, establishing a vital buffer in the event of technical failures or emergency cut-offs.

The El Verde facility remains the single most critical asset in the region's hydraulic network, processing 77 per cent of all water consumed across the Western Costa del Sol - amounting to approximately 45 million cubic metres annually.

The remainder of the region's water resources is supplied through a network of auxiliary sources:

• La Concepción Reservoir: Primary raw surface water source feeding El Verde.

• Marbella Desalination Plant: Produces up to 20 million cubic meters per year.

• Fuengirola River Aquifers: Yields 8.08 million cubic meters annually.

• Guadalmansa River Wells: Contributes 4.92 million cubic meters per year.

• Inter-basin Transfers: Emergency connections with Malaga city (Churriana pumping station) and Campo de Gibraltar.

The renewal effort comes after decades of bureaucratic delays. An earlier expansion attempt initiated in 2005 was halted following the 2008 financial crash, while a subsequent 2023 design tender had to be annulled due to procedural publication errors in the Official Journal of the European Union.

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