The Gila River Indian Community has received federal approval to develop its own water quality standards.
The U.S. Environmental Protection Agency announced the decision Tuesday.
The tribe will develop standards that are at least as stringent as those used by the federal government. The standards are subject to EPA approval.
The tribe's authority is similar to that of states under the federal Clean Water Act.
Mike Stoker is the EPA's administrator for the Pacific Southwest region. He says the tribe will be able to protect water on its reservation, including parts of the Gila and Santa Cruz rivers.
The Gila River Indian Community joins 59 other tribes across the country with the same authority. Six are in Arizona.