MATTOON, Ill. (WAND) - In July 2025, the City of Mattoon sent out multiple "Do Not Drink" advisories after they found microcystin, a harmful algae toxin, in their drinking water.

Since that happened, the city has worked to ensure they don't have any more issues. 

"This past year was the perfect storm, I guess you might say," said David Clark, the public works director for the City of Mattoon. "We had a drought, so shallower water plus heat and plenty of nutrients from the water runoff." 

This year, Clark said the team is being more proactive when it comes to water treatment. They've placed new solar rafts and other equipment in Lake Paradise and Lake Mattoon, which can send data constantly to public works staff. 

The city has also already treated both lakes with an algaecide and plans to treat them again as temperatures increase. They also have backup plans if treatment options don't work as planned. 

In previous years, when the city needed its water tested, they'd have to bring a water sample to the EPA in Springfield and have them test it. Now, the city is getting certified to test the water itself. 

"We are keeping an eye on it every day, all day long, we test it constantly," Clark said. "The EPA is testing with us. Our algae contractor they're also testing. So we're doing a lot of testing. Our tests have been well below the [detection] levels that are allowed." 

Copyright 2026. WAND TV. All rights reserved.