NEWS RELEASE: Report finds more than half of Idaho wastewater treatment plants exceed pollution limits, raising water quality and public health concerns
For Immediate Release: Tuesday, September 1, 2026
Contacts:
Will Tiedemann, Regulatory Program Manager, (208) 345-6933 x 228
Abby Urbanek, Communications & Media Manager, (208) 345-6933 x 214
Report finds more than half of Idaho wastewater treatment plants exceed pollution limits, raising water quality and public health concerns
Boise, ID — The Idaho Conservation League’s (ICL) ninth annual study of Idaho’s wastewater treatment plants found that in 2025, over half (~53%) of plants failed to comply with Clean Water Act permits for the discharge of harmful bacteria, chemicals, toxic metals, and other substances. This represents an increase since 2024, raising continued concerns for public health. During 2025, there were 464 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. However, as has long been the case, too many of Idaho’s facilities fail to meet permit limits—introducing pollutants into waterways, and compromising water quality and ecosystem health.
“Municipal wastewater treatment plants provide an essential service that most of us rarely think about, but when they struggle, those results start to affect us all,” said Will Tiedemann, regulatory program manager with ICL. “Unfortunately, Idaho has not yet been able to reach the milestone where the majority of facilities don’t violate pollution limits—ultimately putting the health of Idahoans at risk.”
As is typical, there is a significant range in the performance of facilities across Idaho. In 2025, some facilities reported zero violations while others reported upwards of 50+ violations. 11 of the worst-performing facilities reported 57% of all violations.
Other findings include:
3 facilities (Preston, Driggs, and Plummer) accounted for 27% of all violations. In 2024 the same facilities accounted for 31% of all violations.
Driggs and Preston contributed the vast majority of all pounds of pollutants discharged over limits (86%), but on the positive side, Preston has recently completed upgrades to its facility while Driggs is in the design stages of upgrading to their facility.
54 cities and towns reported no discharge violations in 2025.
Treatment facilities in towns of Winchester and Genesee completed large-scale treatment plant upgrades in 2025 and have shown dramatic improvements in reducing violations.
ICL issued its first wastewater treatment plant report in 2017. The annual report compiles and examines discharge permit violations for every Idaho facility, and reports on their record of meeting legal standards. The report also serves as a springboard for advocacy by providing Idahoans with a clearer picture of how wastewater permitting works, how well local wastewater treatment plants are meeting their obligations, and how to engage local leaders to act to improve plants with violations.
“At a time when it seems there is less and less water to go around, protecting our clean water is more important than ever,” concluded Tiedemann. “Maintaing the quality of our rivers and lakes is a responsibility communities must uphold every day for the benefit of their citizens. It is far better to remain vigilant and address potential problems now than to deal with greater harm and expense later.”
When wastewater treatment plants consistently fail to hold themselves accountable, ICL isn’t shy to step in. In early 2026, ICL brought litigation against the wastewater treatment plants operated by the cities of Rexburg and Burley for repeated permit violations. That action ultimately led to legal intervention from the Idaho Department of Environmental Quality (DEQ) itself. It is now expected that each city and DEQ will develop a compliance schedule to address permit violations and needed facility upgrades.
ICL will continue to track each facility’s compliance, particularly those with poor track records. Review ICL’s 2026 Wastewater Treatment Plant in its entirety by clicking here.
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ICL’s mission is to create a conservation community and pragmatic, enduring solutions that protect and restore the air you breathe, the water you drink, and the land and wildlife you love.
