Mining major Rio Tinto and the Western Australian government have formed a 50:50 joint venture (JV) to complete the Dampier seawater desalination plant in the Pilbara, a project aimed at improving regional water security and reducing pressure on groundwater resources.

The A$1.1-billion plant, located near Karratha in Western Australia, will supply desalinated water to the West Pilbara Water Supply Scheme, which provides water to several towns and industrial hubs in the region.

Once fully operational, the plant will deliver 8 Gℓ/y of desalinated water to the scheme, reducing abstraction from key aquifers that have been under increasing pressure owing to below-average rainfall in recent years.

Stage 1 of the project is already under construction and is expected to deliver 4 Gℓ/y of desalination capacity later this year. Construction of Stage 2 has also begun and will add a further 4 Gℓ/y of capacity, with first water expected in 2027.

The water will support communities including Karratha, Wickham, Dampier, Roebourne and Point Samson, as well as industrial areas such as Cape Lambert and the Burrup Peninsula. The scheme itself is operated by Water Corporation.

The project is expected to significantly reduce groundwater abstraction from the Bungaroo aquifer and Millstream aquifer, which supply the regional water system. Over the past five years, the West Pilbara has experienced rainfall and streamflow levels below the long-term average, limiting groundwater recharge at these aquifers.

The JV builds on a memorandum of understanding signed in 2025 between Rio Tinto and the Western Australian government to collaborate on strengthening water security in the Pilbara.

Western Australian Premier Roger Cook said the project would support communities and industry in one of the state’s most important economic regions.

“Western Australia has the strongest economy in the nation thanks largely to the Pilbara and our world-leading resources industry. That’s why we want to ensure the Western Australians who live in such an important part of our state have access to the quality infrastructure and services they deserve,” he said.

Cook added that the government was investing heavily in infrastructure that would deliver billions of litres of water to local households and businesses, while also working with the Yindjibarndi Aboriginal Corporation to improve the sustainability of the Millstream aquifer.

Rio Tinto Iron Ore CEO Matthew Holcz said the desalination plant would help reduce reliance on groundwater resources in the region.

“We understand water is a scarce resource, especially in the Pilbara. Bringing on the Dampier Seawater Desalination Plant is an important step as we work to reduce our reliance on groundwater abstraction,” he said.

Holcz added that Stage 1 of the project would reduce the company’s draw on the Bungaroo aquifer, which is of cultural significance to the Robe River Kuruma People, while the partnership with the Western Australian government would improve the long-term sustainability and security of water supply across the Pilbara.