Water Limits Challenge US Southwest Mining Expansion

Washington’s push to mine more copper and lithium in the U.S. Southwest faces significant water shortages. Future mining projects struggle to secure enough water for decades of operation in the region’s driest basins. Nevada and Arizona already show growing water pressure.

Several projects are advancing, including Lithium Americas’ Thacker Pass in Nevada and Ivanhoe Electric’s Santa Cruz near Phoenix. Arizona’s copper industry heavily relies on groundwater as Colorado River flows shrink. Hudbay Minerals’ Copper World project also received $600 million from Mitsubishi.

Miners are responding by buying or leasing existing water rights. Some redesign projects to use less water or engineer around aquifers. Irrigated agriculture consumes about 72% of Arizona’s available water supply. Arizona supplied over 70% of U.S. copper in 2024.

The Colorado River Basin endured its driest 21-year stretch from 2000 through 2020, one of its driest periods in 1,200 years. About half of Nevada’s 250 groundwater basins are over-appropriated, meaning legal rights exceed annual replenishment. Pumping and treatment also add substantial costs for operators.

Nevada’s Big Smoky Valley-Tonopah Flat basin shows severe water stress. Water commitments there are 21,940 acre-feet per year, nearly 3.7 times its estimated perennial yield of 6,000 acre-feet. West Vault Mining leased existing rights for its Three Hills gold deposit in this basin after Nevada stopped issuing new permits.