Lisa Blatt, Oklahoma's lawyer, took issue with virtually every aspect of the district's argument, including the claim that water drawn directly from the river is too salty.
"They think all the water that their residents drink is salty, but they still are drinking it," Blatt said.
The case arose from a federal lawsuit the district filed in 2007 against the Oklahoma Water Resources Board and the Oklahoma Water Conservation Storage Commission that challenges the state's water laws and seeks a court order to prevent the board from enforcing them.
Lower courts have ruled for Oklahoma, including the Denver-based 10th U.S. Circuit Court of Appeals. It found that the Red River Compact protects Oklahoma's water statutes from the legal challenge.
Legislation adopted by the Oklahoma Legislature in 2009 said no out-of-state water permit can prevent Oklahoma from meeting its obligations under compacts with other states. It also requires the Water Resources Board to consider in-state water shortages or needs when considering applications for out-of-state water sales.
The Obama administration is backing the Texas district at the Supreme Court, saying Oklahoma may not categorically prohibit Texas water users from obtaining water in Oklahoma. But the administration takes no position on whether the Texans ultimately should get the water they are seeking in this case.
A decision is expected by late June.
The case is Tarrant Regional Water District v. Herrmann, 11-889.