New report finds more than half of Idaho wastewater treatment plants violated Clean Water Act

BOISE (Idaho Capital Sun) — More than half of Idaho’s wastewater treatment plants violated Clean Water Act pollution discharge limits at least once last year, while some plants routinely violated limits for years, according to a new report by the Idaho Conservation League.

The report, “The seventh annual Idaho Wastewater Treatment Plant Report: Municipal Sewage Treatment Plants in Idaho Failing to Meet Clean Water Act Standards,” found 458 violations in Idaho sewer treatment plants in 2023.

Eleven of the state’s 123 wastewater treatment plants were responsible for most of the violations, about 63%, according to the report. The report also said only a small number of violations result in penalties.

“We need to be holding more of these polluters accountable,” the Idaho Conservation League wrote in the report. “If not, we risk poor water quality, detrimental impacts to aquatic life and human health concerns.”

Where did the data come from for the Idaho Conservation League’s study?

In a phone interview, Idaho Conservation League conservation associate Will Tiedemann, the author of the report, said violating Clean Water Act limits can be harmful to water quality and is against the law.

Tiedemann said he gathered data for the report from public records of violations in Idaho from the United States Environmental Protection Agency’s Enforcement and Compliance History Online website, which is often referred to as ECHO. The data comes from water samples the facilities submit to the EPA as part of monitoring requirements.

The report identified violations for discharge limits for ammonia, E. coli, phosphorus, nitrogen and more.

The report found that wastewater treatment plants in three small communities accounted for 32% – or nearly one third – of all violations in the state.

• City of Driggs: 54 violations in 2023, including for discharging ammonia in violation of legal limits in 2022 and 2023. Driggs’ facility discharges to a tributary of the Teton River, according to the report.
• City of Preston: 51 violations in 2023, including weekly, monthly and annual violations of pollutant limits, primarily for ammonia and nitrogen. Preston’s facility discharges to Worm Creek, a tributary of the Cub River, according to the report.
• City of Parma: 43 violations in 2023. According to the report, the city of Parma has agreed to a settlement with the Idaho Department of Environmental Quality that assessed a $66,900 penalty for 92 violations dating to 2018. According to the report, Parma’s facility discharges to Sand Hollow Creek, which enters the Snake River about five miles downstream.

Efforts to reach officials with the cities of Parma and Preston were unsuccessful.

Tiedemann said the report highlights the importance of clean water in Idaho and the Idaho Conservation League’s core values of protecting air, water, land and wildlife.

High levels of ammonia in water can kill aquatic organisms and have a cascading effect on bodies of water, Tiedemann said. E. coli found in animal and human waste can cause serious injury or death, while phosphorus and nitrogen can cause excessive algae growth, which can deplete oxygen in waterways. Water with toxic algae growth can be hazardous or fatal for animals to drink.

Tiedemann hopes people will look up how their community performed in the report and take action by demanding clean, safe water and plans to improve violations.

Officials in one Idaho community with numerous Clean Water Act violations plans to design a new plant

Officials in Driggs are responding to the violations by taking on a long-term project of designing a new wastewater treatment plant.

“We are aware of those reports, and we are working with the Department of Justice and the EPA and we are in the middle of designing a new plant,” Driggs Mayor August Christensen said in a phone interview.

Located in the shadow of the Teton Range in eastern Idaho, Driggs had a population of 1,984 people in the 2020 Census.

Christensen did not yet have any information about a timeline or cost of the project.

Wastewater sewer treatment plants are among several infrastructure needs piling up across the state, according to a report from the nonprofit organization Lift Local Idaho. The report identified $4.7 billion in infrastructure needs across the state between wastewater, road and bridge, water, airport, public transportation, energy and cybersecurity projects. The report identified $1.4 billion in wastewater infrastructure demands in 84 projects across the state – including an estimated $30 million for a wastewater project in Driggs.

Officials with the Association of Idaho Cities and Clearwater Financial gathered data for the Lift Local Idaho infrastructure report using surveys that represented 149 Idaho cities. Lift Local Idaho supports a local option sales tax for funding local projects.

The Idaho Conservation League’s report praised efforts in Driggs to make long-term improvements.

“We are encouraged by the solid progress the City of Driggs has made to address the longstanding issues with their (wastewater treatment plant),” the report states. “For most small towns in Idaho, constructing new a (wastewater treatment plant) is a significant challenge that requires considerable resources that can strain municipal budgets and staffing.”

Report also highlighted bright spots among sewer treatment plants

It wasn’t all bad news, however. The report found that 47 Idaho cities or towns had zero wastewater treatment plant violations in 2023. Communities including American Falls, Caldwell, Burley, Lewiston, McCall, Nampa, New Plymouth, Rigby, Weiser and others had zero violations in 2022 or 2023.

Other communities, like Melba, Jerome, Kune, Nez Perce, Mullan, Smelterville and Craigmont were highlighted for reducing the number of violations and the overall progress those communities made.