EPA Reaches Agreement with Navajo Tribal Utility Authority to Improve Wastewater Treatment

FLAGSTAFF – The U.S. Environmental Protection Agency (EPA) announced two settlements with the Navajo Tribal Utility Authority (NTUA) to address non-compliance with its Clean Water Act wastewater programs. NTUA operates the Shiprock and Window Rock wastewater treatment plants, which discharge treated wastewater within the boundaries of the Navajo Nation.

The two treatment plants collect and treat sewage from five communities in the Navajo Nation, serving over 13,000 people. The Shiprock plant serves the community of Shiprock, and discharges treated water into the San Juan River, while the Window Rock plant serves the communities of Fort Defiance, St. Michaels, Tse Bonito, and Window Rock and discharges treated wastewater into Black Creek.

“Through these compliance orders, the Navajo Tribal Utility Authority will work to improve the operation and maintenance of its UV disinfection systems at the Shiprock and Window Rock treatment plants,” said EPA Pacific Southwest Regional Administrator Martha Guzman. “EPA is working with the Authority to ensure wastewater discharges meet the highest standards, protecting the San Juan River and Black Creek and safeguarding the health of Navajo Nation communities.”

Following an August 2021 inspection of the Shiprock plant, EPA determined that NTUA’s wastewater treatment did not comply with federal Clean Water Act regulations. The plant discharged wastewater that exceeded the permitted limit for E. coli concentrations. These exceedances were caused by inadequate operation and maintenance of the ultraviolet disinfection system.

After completing a November 2021 inspection, EPA similarly determined inadequate operation and maintenance of the ultraviolet disinfection system at the Window Rock plant caused multiple exceedances of the limit for E. coli concentrations between April 30, 2020, and June 30, 2022.

Wastewater with high concentrations of E. coli discharged into waters such as the San Juan River and Black Creek poses risks to public health. Coming into contact with water containing elevated levels of E. Coli can cause illnesses that induce vomiting and diarrhea and may indicate the presence of other disease-causing viruses and bacteria.

Learn more about EPA enforcement requirements and wastewater management under the Clean Water Act on EPA’s Water Enforcement webpage.

For more information on reporting possible violations of environmental laws and regulations, visit EPA’s enforcement reporting website.