The study that called desalinated water from Mexico feasible
Desalination removes salt from seawater to make it drinkable. Arizona has no coastline, so desalinated water from Mexico would come from a plant on the Mexican coast, an idea a government study called feasible 6 years ago. In 2020, engineers working under Minute 323 of the 1944 United States Mexico water treaty found that desalinating water from the Sea of Cortez near Puerto Penasco, Mexico, is technically and economically feasible, delivering water to the border for 2,050 to 2,228 dollars per acre foot, an acre foot being enough water to cover 1 acre 1 foot deep. Reaching the full 200,000 acre foot a year target would need 2 plants built together, at a combined capital cost of 4.5 to 4.9 billion dollars.
Why Arizona wants this water
Arizona faces a water deficit projected at 335,800 acre feet a year by 2035, the largest United States figure in the study behind Southern California.
United States figures are projected for 2035. Mexico figures are projected for 2030. Both come from the same binational study.
Show the numbers
| Southern California | 574,000 |
| Arizona | 335,800 |
| Western Sonora, Mexico | 112,700 |
| Nevada | 85,000 |
| Northern Baja California, Mexico | 46,700 |
The same study lists what still has to happen before construction could begin, including securing pipeline right of way and confirming that the Federal Electricity Commission of Mexico would supply the plant power, since no binational framework yet exists for trading water this way. That detail comes only from the full 31 page executive summary of the study, not the 2 page public summary.
A private company version collapsed within weeks
In December 2022, a private company, IDE Technologies, proposed its own 5.5 billion dollar desalination plant at Puerto Penasco, claiming the deal could supply Arizona for at least 100 years. The Joint Legislative Water Committee agreed on December 20, 2022 to keep talking with the company, and the federal government of Mexico backed the plan weeks later, on condition that no local opposition existed. That condition broke the deal.
Please do not tell me to move quickly as if we have to get it done by January 5.
Lisa Otondo, then a state senator on the Joint Legislative Water Committee. Source 4.
It just feels like so much of all this was an inside track.
Rebecca Rios, a state senator on the same committee. Source 4.
By late January 2023, a Sonoran businessman who had publicly backed the project, Oscar Serrato, reversed his position and said on social media that the government of Sonora would not work with IDE. Decision authority over any such deal rests with the federal government of Mexico, not the state government of Sonora, according to the same reporting.
Arizona is not building a desalination plant in Mexico
As of August 2026, nothing has been built. Arizona is bracing for cuts of at least 760,000 acre feet a year from its 2.8 million acre foot Colorado River allocation, and the Assistant Interior Secretary, Andrea Travnicek, says the next round of required cuts will likely total 1.5 million acre feet, with 1.25 million split between Arizona, California and Nevada and the rest from Mexico.
The last 2 rows are not separate amounts to add together. The second contains the first plus the share coming from Mexico.
Show the numbers
| Arizona Colorado River allocation | 2,800,000 |
| Cuts Arizona is already bracing for | 760,000 |
| Next proposed cut, Arizona, California and Nevada combined | 1,250,000 |
| Next proposed cut, all sources including Mexico | 1,500,000 |
The Water Infrastructure Finance Authority of Arizona had 1 billion dollars committed in 2022 for its Long Term Water Augmentation Fund, and about 386 million dollars of that remains. The agency is funding 2 projects today, a California groundwater exchange with Epcor and an upgrade to a wastewater plant that purifies Tijuana, Mexico sewage in exchange for part of the Mexico Colorado River allocation. Neither is Sea of Cortez desalination. Central Arizona Project water costs more than 300 dollars an acre foot today, against thousands of dollars for desalinated seawater.
We only get one shot at doing this right. So we don't have the luxury of false starts, of stopping and starting over.
Chelsea McGuire, director of the Water Infrastructure Finance Authority of Arizona. Source 5.
A government study called Sea of Cortez desalination feasible in 2020. A private company version of the same idea collapsed within weeks in 2023. The agency actually paying for new water today is funding 2 other projects instead, with Sea of Cortez desalination only described as coming up for review before the end of 2026.