Interior Finalizes Colorado River Cuts for Arizona as Chip Fabs Expand

Arizona’s chip boom is running into a new infrastructure constraint: a federal Colorado River plan will cut the state’s supply by at least 760,000 acre-feet a year beginning in 2027. The reduction arrives as TSMC and Intel add capacity for advanced AI chips in a desert state where replacement water will require new infrastructure and higher costs.

The U.S. Department of the Interior finalized the plan in August after the basin states failed to reach their own agreement. It sets steep reductions for Arizona, Nevada, and California, with Arizona facing the largest loss. The cut will begin in 2027, turning a long-running drought challenge into a deadline for the state’s cities and manufacturers.

The timing matters because semiconductor fabrication uses ultra-pure water to clean and etch chips. Producing that highly treated water requires more municipal water through deionization and reverse osmosis. A typical facility might use 10 million gallons of ultra-pure water a day and require as much as 16 million gallons of municipal water to do it.

TSMC has received up to $6.6 billion in CHIPS Act funding and plans to build at least six semiconductor fabs in Phoenix. Its first Arizona fab currently recycles 65 percent of the water it uses, according to the company, and TSMC says that figure should reach at least 90 percent once a planned reclamation plant is complete.

Intel is also building out in Arizona. The company received a $7.86 billion government grant and plans to spend $32 billion on two new factories and an expansion of an existing facility. Its Chandler operations withdrew more than 2.7 billion gallons of freshwater in 2025, according to Intel’s latest corporate responsibility report.

Arizona’s chip centers are not equally exposed to the river. Maricopa County, home to the TSMC and Intel facilities, relies primarily on groundwater, while water from the Colorado and Salt rivers provides close to 40 percent of its supply. Local leaders say they have prepared for cuts with water stored underground and other surface-water sources, reducing the prospect of an immediate shortage.

Preparation does not make the transition free. New wells and pipes needed to draw on alternative supplies are expected to be a major driver of higher water bills over time. Phoenix charges the same water rates to companies, residents, and other commercial customers, meaning TSMC will face the same citywide price increases as its neighbors.

That leaves Arizona with a narrower choice than simply approving more chip investment. The state can maintain manufacturing growth while adapting its water system, but the cost of that adaptation will be shared across a region already managing a reduced river supply. Whether recycling, stored water, and new infrastructure can keep pace with additional fab capacity is now the practical question before 2027.