UPDATE: 7/11/25 1:30 p.m. - According to the Coles County Health Department, IEPA has obtained samples from their water facility for further testing. Results are pending and will be provided by the IEPA by 2 p.m. on Saturday.
The IEPA released the following statement regarding the status of the city water:
“Given the current scientific understanding, it is unlikely that showering, bathing, washing hands, doing laundry, etc., in tap water with cyanotoxin levels near or below the Health Advisory will be harmful to human health.
However, infants and young children under the age of six should be supervised while bathing and during other tap water-related activities to prevent accidental ingestion of water. You may also accidentally consume water that is used to prepare or wash your food, make beverages, or make ice.”
MATTOON, Ill. (WAND) — The Coles County Health Department says there is no timeline yet for when the "Do Not Drink" advisory will be lifted for the City of Mattoon after tests run on the city’s water supply revealed the presence of microcystin, a harmful algae toxin.
The health department told WAND News Friday morning that the bare minimum time frame to know whether the water is safe again would be 24 hours, but they do not anticipate it being resolved that soon.
"We're doing what we can and working with the City of Mattoon to get resources to the community," Gloria Spear, Environmental Health Director for the Coles County Health Department, said.
According to officials, samples taken from the Mattoon Water Treatment Plant detected microcystin levels at 0.35 parts per billion (ppb)—exceeding the state’s advisory threshold of 0.3 ppb. The toxin is linked to harmful algal blooms and can pose serious health risks if consumed.
Concentrations of toxin are just above the threshold Illinois set for children.
- Harmful lever for adults: 1.6 µL/L
- Harmful level for kids: 0.3 µL/L
- Mattoon's level: 0.35 µL/L
Residents should not drink tap water, only use bottled water for drinking, preparing food and baby formula, brushing teeth, washing dishes, and making ice. They should also not attempt to treat the water. Boiling, freezing, filtering, or adding disinfectants will not remove the toxin.
People are urged to continue to use bottled water until further notice.
The algal bloom was caused by the hot, sunny conditions the area has seen lately.
Symptoms of poisoning with this microtoxin are similar to norovirus (stomach issues). It can cause a rash if on the skin, however, ingesting it is worse than contact on the skin.
Spear said it is hard to test for infection since it is so rare.
It is recommend pets receive bottled water.
In an advisory, the city said it will notify the public once tests confirm that the water is safe to drink again.
For more information contact Mattoon Water Plant at 217-234-2454 or Coles County Health Department at 217-348-0530
Sarah Bush Lincoln Hospital posted on Facebook writing, "Even though Mattoon water is unsafe for use, Sarah Bush Lincoln is fully operational and safe for patients, visitors and staff. We are using an alternative water source and have flushed our system to ensure safety and cleanliness." The hospital said they were able to switch to another source which provides water from outside the city.
Mattoon businesses and restaurants have been taking to social media to announce whether they will still be open.
This advisory was issued on July 10, 2025, and remains in effect until further testing clears the water supply.
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