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July 12, 2025 1:00 p.m. UPDATE IEPA sampled the water on the morning of Friday, July 11th. Results from that testing obtained today were found to have an algal bloom neurological toxin at .314 parts per billion level, down from .35 parts per billion from our previous testing. The advisory level for a DO NOT DRINK order is .3 parts per billion. While the levels have significantly decreased because of the treatment activities, the toxin levels are still over the recommended limit and the DO NOT DRINK order will continue. At this time, the City has taken more samples and [...]

FAQs About City of Mattoon Water Situation Q: What’s the issue with our water? A: On Thursday, July 10th, the City was notified by IEPA that water contained trace amounts of microcystin (micro-sys-tin), a cyanotoxin (sigh-an-o-toxin) produced by a kind of cyanobacteria that is commonly called “blue-green algae.” While the City continually monitors the water quality, tests performed by the IEPA happen on a periodic basis and when deemed necessary. The water tested at a .35 parts per billion level and the advisory level for children preschool age and younger (under 6 years old), pregnant women and nursing mothers, individuals [...]

July 11, 2025 1:30 P.M. IEPA has been at our water facility site and obtained samples. Results are pending and will be provided by the IEPA by 2:00 p.m. tomorrow. IEPA has advised the following: "IF A DRINKING WATER ADVISORY IS ISSUED, IS THE TAP WATER SAFE FOR OTHER USES OTHER THAN DRINKING?" "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 [...]

July 11, 2025 11:00 a.m. The City of Mattoon is currently in communication with IEPA and the Coles County Health Department. We are following their guidance and aggressively treating the water. The City is awaiting further sampling and testing from the IEPA. Once further guidance is provided by the Coles County Health Department and the IEPA, we will share that information with the public.    

City of Mattoon water is possibly contaminated with (Microcystin) a Harmful Algal Bloom DO NOT DRINK YOUR WATER Failure to follow this advisory could result in illness. A DO NOT DRINK ORDER is being issued because a harmful algal bloom neurological toxin were found at 0.35 parts per billion level and the advisory level for a DO NOT DRINK order is 0.3 parts per billion. The Coles County Health Department, and City of Mattoon Water Treatment Plant are advising residents of the City of Mattoon Water Treatment Plant to NOT USE THE TAP WATER FOR DRINKING AND COOKING UNTIL FURTHER [...]