Mexico says it will be delivering more water to Texas than it had earlier agreed to, but it's still not enough to satisfy a long-held treaty.
Details of a new deal between the US Department of Agriculture, which made the announcement, and Mexico are still to be announced.
"Mexico has been saying they're in a prolonged drought, that the water that they owe the Rio Grande Valley and the United States is not available because of a lack of water resources," according to Gary Joiner, the Texas Farm Bureau's Director of Communications.
"We dispute that finding. We believe there is available water and their latest announcement alludes to that, that in international reservoirs that they have control over, they have water, they can release water and make water available."
Under a 1944 treaty, Mexico is required to deliver 1,750,000 acre-feet of water to the US every five years, but the nation has gotten very behind in recent years.
"Mexico owes more than one million acre-feet of water currently to the Rio Grande Valley for both farmers and municipalities so they are well behind what is required by the treaty," Joiner says.
"We've already lost sugar cane production in the Rio Grande Valley, the sugar mill that was owned by growers has closed.
"We're fearful that citrus, grapefruit, oranges from Texas may be the next crops to be impacted by lack of water, and maybe even cotton after that," Joiner adds.
"So this is serious. Water is needed and needed right away, and Mexico says it will begin to make that commitment."
Under terms of a new understanding, Mexico says it will immediately transfer more than 56,000 acre-feet at the jointly-managed Amistad Reservoir.