Catarina de Albuquerque, a Portuguese lawyer contracted by the United Nations to examine safe drinking water and sanitation, called on the U.S. government to do more to level the playing field for waste and water.
"I am concerned that several laws, policies and practices, while appearing neutral at face value, have a disproportionate impact on the enjoyment of human rights by certain groups," she said in a statement.
She said following a fact-finding mission to the United States that at least 13 percent of the American Indian population doesn't have access to drinking water or wastewater disposal. That is in contrast to the 0.6 percent reported for other households.
"Access to water and sanitation is further complicated for indigenous people in the U.S. depending on whether they are part of a federally recognized tribe or not," de Albuquerque said.
She said it was important for Washington to understand that access to safe drinking water and sanitation is a fundamental right for all communities.
"I call for legal action to change the status of unrecognized and terminated tribes to enable all American Indians to gain the respect, privileges, religious freedom and land and water rights to which they are entitled," she said.