"It was suggested that this one may be completed within two years," Attorney General Henry McMaster told state lawmakers and environmental leaders. "But with the addition of these interveners, of course that has stretched it out. So we really don't know."
In 2007, Mr. McMaster filed a federal lawsuit to stop North Carolina from draining water from the 225-mile long Catawba River, which provides drinking water to 1.3 million people. The U.S. Supreme Court has agreed to consider the case.
Last year, the special master appointed by justices to help resolve the dispute allowed the city of Charlotte, Duke Energy and a water system serving Union County, N.C., and Lancaster County, S.C., to enter the case and submit arguments of their own.
Mr. McMaster says the case should be between the states, not individual municipalities or other entities.
North Carolina has said its water needs pose no imminent threat to its neighbor. A message left for North Carolina Attorney General Roy Cooper's office was not immediately returned.
The litigation is costly. Last year, Mr. McMaster got $1.2 million to fight the case. This year, he's asking state lawmakers for nearly double that, $2.2 million.