The Supreme Court on Friday rejected a settlement between Western states over the management of one of North America’s longest rivers.

The 5-4 decision rebuffs an agreement that had come recommended by a federal judge overseeing the case over how New Mexico, Texas and Colorado must share water from the Rio Grande. The high court found that the federal government still had claims about New Mexico’s water use that the settlement would not resolve.

U.S. Circuit Judge Michael Melloy had called the proposal a fair and reasonable way to resolve the conflict between Texas and New Mexico that would be consistent with a decadeslong water-sharing agreement between the two states as well as Colorado.

The federal government, though, lodged several objections, including that the proposal did not mandate specific water capture or use limitations within New Mexico.

New Mexico officials have said implementing the settlement would require reducing the use of Rio Grande water through a combination of efforts that range from paying farmers to leave their fields barren to making infrastructure improvements. Some New Mexico lawmakers have voiced concerns, but the attorney general who led the state’s negotiations had called the agreement a victory.

Farmers in southern New Mexico have had to rely more heavily on groundwater wells over the last two decades as drought and climate change resulted in reduced flows and less water in reservoirs along the Rio Grande. Texas sued over the groundwater pumping, claiming the practice was cutting into the amount of water that was ultimately delivered as part of the interstate compact.

The proposed settlement would recognize several measurements to ensure New Mexico delivers what’s owed to Texas. New Mexico, meanwhile, agreed to drop its challenges against Texas in exchange for clarifying how water will be accounted for as it flows downstream. The agreement also outlined transfers if not enough or too much water ended up in Texas.