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Residents raise concerns over delayed cooling system at Town of Erin wastewater treatment plant

March 12, 2026   ·   0 Comments

By Riley Murphy

Local Journalism Initiative Reporter

It was 2018 when Belfountain resident Ann Seymour, who had lived there for over 20 years, was standing in line at a grocery store when a nearby resident turned to her and asked if she had heard of the Town of Erin’s proposed wastewater treatment plant.

The effluent from the treatment plant is planned to flow directly into the West Credit River, the very river Seymour’s property backs onto.

Eight years later, the treatment plant is still on Seymour’s mind daily.

The Town of Erin’s wastewater treatment plant is being built to service Erin and Hillsburgh. The plant will help the Town accommodate future and current development and growth.

In August of 2019, the Town of Erin received the Ministry of the Environment, Conservation and Parks’ approval of the completed Municipal Class Environmental Assessment, allowing the Town to proceed with the creation of wastewater solutions. 

The plant is designed to discharge treated effluent into the West Credit River.

As part of an Environmental Compliance Approval, the Town must cool the effluent to 19 degrees Celsius before it enters the river.

This includes covers and shades over tanks and clarifiers, mechanical chillers, and the pre-cooling of heated water by future water-intensive businesses, and the approval also includes future monitoring of river water.

Part of this is thanks to the Coalition for the West Credit River.

The coalition was formed in 2020, but a group of community members and concerned residents had formed back in 2018.

Seymour was part of the original group, and she explains that the official coalition was formed after a presentation in 2020, during which their group spoke on the West Credit River downstream from Wellington County and showed attendees Redds.

Redds are a type of spawning bed for certain species of trout, particularly brown and brook trout, and Seymour explains that these redds were found throughout the West Credit River, where the treated effluent would be flowed into.

In their presentation, she explains that they noted a healthy population of brook trout still present in the West Credit River.

“What we’re trying to do is protect a last remaining reach of cold water ecosystem,” says Seymour. “That was the beginning, and then everybody said, ‘Hey, wait a minute, we can’t lose this reach of the river with this ecosystem in it. Let’s work together to try to mitigate the design for the wastewater treatment plant.’”

Brook trout thrive at 19 degrees Celsius, and with effluent flowing into the West Credit River, the coalition feared the potential increase in temperature would affect the species.

John Monczka from Freshwater Conservation Canada describes the West Credit River as a “special place.”

“That’s the way I refer to it because a lot of people don’t know that you’ve got this resource, a self-sustaining native brook trout population, within about an hour and a half’s drive of close to six million people, which is pretty special given what we’ve done to Southern Ontario,” he says.

He adds that typically, more cold water systems existed in Southern Ontario prior to development, “through development, channelization, lack of forest cover, taking everything down, and pollution coming in, you’ve basically destroyed the majority of the brook trout habitat, streams that lead to Lake Ontario.”

In 2019, the Ministry of the Environment, Conservation and Parks had initially approved the proposed treatment plant, saying that “an individual environmental assessment is not required,” reads the letter on the Town of Erin’s website. 

The report on the plant, says Monczka, reads that the maximum effluent temperature would be 19 degrees.

Many of the streams in this area get quite warm, he says, and any addition could potentially raise the temperature.

Seymour says that the temperature taken when the initial study was done was “the coolest year within 10 or 12 years,” which she explains lacks an overall average for the study.

So, in 2021, the group took it upon themselves to set up water-temperature monitoring devices near the outfalls of other sewage treatment plants in the area, and in the summer, they recorded temperatures as high as 22 degrees.

“We took that to the Ministry and said this is what we found, and we believe that there has to be something done to chill the effluent,” retells Monczka. In May of 2022, he says, an Environmental Compliance Approval was issued, noting that the effluent must be cooled before discharge into the river.

This would be Canada’s first municipal effluent-cooling system incorporated into the facility’s design, but the Town has experienced delays with the system.

“March the 6th, 2026, and we don’t have a cooling system installed,” says Monczka.

On February 12, at the Town of Erin’s Council meeting, former Caledon councillor Ian Sinclair delegated on behalf of the coalition.

He noted the coalition’s concerns regarding the delay.

“We have received, last Friday, some essentially plumbing diagrams of a cooling system, but no information of what those diagrams really meant,” said Sinclair at the meeting. 

“The Ministry of Environment issued the Certificate of Approval on May 3, 2022, over three years ago, requiring an effluent cooling system designed to reduce effluent temperature, and apparently, the Town of Erin Council has requested the Ministry of Environment allow a delay in operation of the effluent cooling system.”

He also voiced concerns about potential impacts on the West Credit River and the brook trout population, as well as questions about the current construction.

Town of Erin Council members expressed their appreciation for the coalition, their work, and their solidarity with the coalition.

Monczka adds that they have asked Council questions regarding the delay, but have received no answers.

“To not have that cooling system ready to go along with the operation of the plant treating sewage, leaves a big question mark in our heads,” he says.

This was not the first time the coalition has delegated; it previously came to the Town of Erin Council on December 13, 2023, and to Peel Region on January 27, 2022, June 9, 2022, and April 24, 2025.

They have also continued to connect with First Nations and Mississaugas of the Credit First Nation as part of their ongoing advocacy.

Part of their concerns also account for climate change, as Monczka says the summers are only going to get warmer.

He explains the Coalition is not alone in this; groups such as the Belfountain Community Organization, Ontario Streams, and Ontario River Alliance have joined them to advocate for the brook trout population and the preservation of the cold-water system.

A lot of their worry stems down to the Credit taking this amount of effluent.

When the facility is designed to emit an average of 7.2 million litres of treated effluent per day.

“It’s a small, sensitive receiver for 7.2 million liters of effluent,” says Seymour, noting the estimated amount.

For the coalition, it’s not just the environmental impacts, but also the communication issues they’ve experienced.

As Caledon residents, Seymour explains there was no communication.

“Having a border is problematic. That part of this ecosystem is in Erin or Wellington County, and the other is in Caledon, and there was no downstream consultation with residents,” she says.

But her concern is not just as a resident neighbouring the credit, “my concern is the ecosystem,” she says.

As a past environmental educator, Seymour says she “cannot live with taking away another species’ habitat.”

“That’s why I speak up about this river and try to protect this river,” she says. “I’m just so grateful that these other groups are helping and involved in seeing this beautiful species still living here.”

She adds that it is important not only to protect native species and the integrity of the cold-water ecosystem, but also the benthic life.

“It is extraordinary how much insect life is still on this river, and my concern is that that will disappear,” says Seymour. “My fear is that upstream development comes at the cost of this river.”

An effect on one will affect all, she continues to explain, noting the various bird species that come to the West Credit River.

“You’ve got a diversity of species here. This is what’s living here, and it’s all tied together with maintaining. If you didn’t have all these trees here and your water here, your list might be a lot shorter,” says Monczka.

As a former educator, Seymour has continued that in her advocacy, bringing school groups to the river to view both the bird-monitoring device and their livestream underwater fish cam, both in the West Credit River.

Outreach and education are something she says they have done a lot of over the years.

“The more you educate, the better people understand.”

Since the treatment plant was brought forward, Seymour says they have been working constantly.

“Lots of presentations, panel discussions, school visits,” she says. “We’ve been at this a long time.”

Next steps for the coalition, they say, look like connecting with Council and, hopefully, hearing answers to their long-standing questions.

“Looking at those kinds of issues, hopefully going forward, there’s great lessons to be learned from this situation,” says Monczka.

The Town of Erin was contacted for comment, but no response was received by press time.

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