Report finds over 50% of Idaho’s wastewater treatment plants are violating pollution discharge limits, raising concerns over water quality and public health
For Immediate Release: Wednesday, September 3, 2025Contact:Will Tiedemann, Regulatory Conservation Associate, (208) 345-6933 x 228Abby Urbanek, Communications and Marketing Manager, (208) 345-6933 x 214
Report finds over 50% of Idaho’s wastewater treatment plants are violating pollution discharge limits, raising concerns over water quality and public health
Boise, ID — The Idaho Conservation League’s (ICL) eighth annual study of Idaho’s wastewater treatment plants found in 2024, over half (50.5%) 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.Wastewater treatment plants play a critical role in safeguarding water quality and human health by ensuring sewage and industrial waste are properly treated before being released back into the environment. Yet, too many of Idaho’s facilities are falling short—introducing pollutants into waterways, and compromising water quality and ecosystem health. ICL’s report provides Idahoans with a clearer picture of how wastewater permitting works and how well local wastewater treatment plants are meeting their obligations. “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.”There is a significant range in the performance of facilities across Idaho. In 2024, some facilities reported zero violations while others reported upwards of 50 or 60 violations. 11 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.Other findings:
- 12 of the 113 sewage treatment plants spread across Idaho were responsible for roughly two-thirds of all violations reported statewide.
- 3 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.
- 56 cities and towns reported no discharge violations in 2024.
- Treatment facilities in communities like Payette, Star, and Filer—which have had no effluent violations between 2021 and 2024—have shown what’s possible through consistent investment, strong oversight, and commitment to protecting public health and the environment.
“Clean water is not a luxury—it’s a right,” concluded Tiedemann. “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.”ICL will continue to track each facility’s compliance, particularly those with poor track records. Review ICL’s 2025 Wastewater Treatment Plant in its entirety by clicking here.
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