Desalination Surges in Chile, But Farmers Left Behind

View of a plant owned by Aguas Antofagasta, a company created 20 years ago that now has three desalination plants to supply drinking water to 184,000 families in that desert city in northern Chile. Credit: Courtesy of Acades

View of a plant owned by Aguas Antofagasta, a company created 20 years ago that now has three desalination plants supplying drinking water to 184,000 families in the desert city of Antofagasta, northern Chile. Credit: Courtesy of Acades

Desalination projects are booming in Chile, with 51 plants planned to process seawater and a combined investment of US$24.45 billion. However, these initiatives hardly benefit small-scale farmers—already threatened by prolonged drought—and have raised environmental concerns.

A survey by the Capital Goods Corporation and the Chilean Desalination and Reuse Association (Acades) revealed that these projects, now in the engineering and construction phases, will add 39,043 litres of water per second in production capacity.

“Using seawater—desalinated or saline—and reusing wastewater relieves pressure on rivers and aquifers, ensuring water for people, ecosystems, and productive activities,” said Rafael Palacios, Executive Director of Acades.

Fifteen of these projects belong to the mining sector, eight to industry, eight to water utilities, and 20 are linked to green hydrogen, a clean but water-intensive fuel that Chile aims to produce on a large scale.

Of the planned plants, 17 are located in the desert region of Antofagasta, in northern Chile, which lies between the Andes mountains and the Pacific Ocean. Eleven projects are in Magallanes in the far south, followed by Atacama, Coquimbo, and Valparaíso in the north and centre, where most of the investment is concentrated.

Palacios said Chile “faces a scenario in which water availability in northern and central Chile could decrease by up to 50% by 2060, so we cannot continue to depend solely on continental sources.”

Currently, 23 desalination plants are operating in Chile with a capacity of 9,500 litres per second. They primarily serve the mining, industrial, and domestic sectors.

Small-scale farmers benefit

Dolores Jiménez, president of the Association of Agricultural Producers of Altos de la Portada in Antofagasta, said their 90-member cooperative, which owns 100 hectares of hydroponic farms, has access to water through an agreement with Aguas Antofagasta.

“We have no water problems thanks to our agreement. We have created an oasis that would otherwise not exist,” Jiménez told IPS by telephone from Antofagasta.

Aguas Antofagasta, a private company that has been operating for 20 years, desalinates water in three plants located in Antofagasta, Tocopilla, and Tal Tal, supplying 184,000 families. It draws seawater through offshore pipes and discharges the brine safely back into the ocean.

The company’s water supply project also supports small farmers who grow carrots, broccoli, zucchini, cucumbers, medicinal herbs, and edible flowers.

“They supply us with water from the pipeline to Mejillones. They financed the connection for six 30,000-litre tanks, from which we distribute the water using a tanker truck,” Jiménez said.

Thanks to a state-funded National Irrigation Commission project, the farmers recently secured 280 million pesos (US$294,000) to build an inter-farm pipeline network that will deliver water directly to 70 plots — a major cost-saving improvement.

In Pullally, a village in the Valparaíso region, farmer Jesús Basáez switched from strawberries to quinoa after the groundwater became too saline due to drought and seawater intrusion.

Known as the “King of Quinoa,” Basáez cultivates three hectares of white, red, and black quinoa using well water. The University of Playa Ancha installed a mobile desalination unit on his farm that uses reverse osmosis to remove salts harmful to crops.

After three years of research, Basáez confirmed that desalination makes strawberry farming viable again, but the high cost — around US$84,000 for the mobile plant — prevents replication on a larger scale.

Debating the effects of desalination

Chile has been facing a prolonged drought since 2010, with water deficits averaging 30 per cent. Severe droughts in 2019 and 2021 were followed by a brief recovery in 2024, but the overall shortage continues.

A study by the Climate and Resilience Center (CR2) at the University of Chile warned that groundwater extraction exceeds aquifer recharge, causing a steady decline in reserves.

Many existing desalination plants use short outfalls installed along a crowded coastline shared by aquaculture operations, artisanal fishers, and indigenous communities.

The main concern centres on the discharge of brine, the salty by-product of the desalination process.

“I will never oppose efforts to secure water for human use. But this highly concentrated brine affects the seabed, where many benthic organisms live. The local impact has never been fully assessed,” said Laura Farías, a researcher at the University of Concepción and CR2.

She noted that brine discharge can harm marine ecosystems at multiple stages of biological development — from larvae to adult organisms — and even affect pelagic species that can move away.

According to Farías, desalination may be seen as a “maladaptation,” as its environmental impacts can ultimately harm coastal communities that depend on marine resources.

However, Acades director Palacios holds a different view.

“The environmental impacts of desalination are legitimate concerns, but evidence and modern technology show they can be effectively managed,” he said.

“In Chile, recent studies show no significant impact from desalination operations, thanks to constant monitoring and advanced diffusion systems. In most cases, natural salinity levels return within two or three seconds and less than 20 metres from the outfalls,” he added.

Palacios also cited research from the University of Playa Ancha showing salinity increases of less than five per cent within 100 metres — and below three per cent within 50 metres in areas like Caldera.

“We are already implementing the first Clean Production Agreement in desalination and water reuse, in partnership with the state’s Agency for Sustainability and Climate Change, to promote sustainable management, transparency, and stronger community relations,” he emphasized.