Report: Some Idaho wastewater treatment plants violating pollution discharge limits

The Idaho Conservation League’s eighth annual study of Idaho’s wastewater treatment plants found in 2024 just over half of plants failed to comply with Clean Water Act permits for the discharge of harmful bacteria, chemicals, toxic metals and other substances. 

During 2024, there were 474 violations of the Clean Water Act among wastewater treatment plants in Idaho, according to a press release.

“Municipal wastewater treatment plants are on the front line for protecting water quality and human health,” said Will Tiedemann, regulatory conservation associate with ICL. “Yet, half of these plants are violating their pollution discharge limits — an unacceptable situation for something so essential as clean water.”

ICL said its report provides Idahoans with a clearer picture of how wastewater permitting works and how well local wastewater treatment plants are meeting their obligations. 

There is a significant range in the performance of facilities across Idaho. 

In 2024, some facilities reported zero violations while others reported upward of 50 or 60 violations. Eleven of the worst-performing facilities were located in relatively small rural communities; a similar trend was also identified in ICL’s 2024 and 2023 assessments, the release said.

Other findings:

• Twelve of the 113 sewage treatment plants spread across Idaho were responsible for roughly two-thirds of all violations reported statewide. 

• Three facilities (Preston, Driggs and Plummer) accounted for 31% of all violations.

• The Rexburg facility, which discharges to the South Fork of the Teton River, had a total of 14 violations in 2024. These violations appear related to two specific incidents last year in which the facility discharged over 40,000 pounds of pollutants over limits. 

• Fifty-six cities and towns reported no discharge violations in 2024. 

“Clean water is not a luxury — it’s a right,” Tiedemann said. “Every Idahoan deserves clean water, reliable infrastructure and those in charge of protecting them to be held accountable. Idahoans and local leaders who live in areas with facilities that have violations need to act now to fix the problem — or they risk continuing to put our water, health and future at risk.”