Water Quality Update – July 21, 2025

July 21, 2025

CITY OF MATTOON

WATER QUALITY UPDATE – July 21, 2025

Current Sample

  • Sample collected on July 21st showed non-detectable levels of harmful algal bloom neurological toxin in the drinking water at 0.14 ppb which is considered non-detect under the EPA recommended advisory levels of .30 ppb.

Past Samples

  • Samples collected on July 16th showed harmful algal bloom neurological toxin in the drinking water at .215 ppb which is under the EPA recommended advisory levels of .30 ppb.
  • Samples collected on July 17th showed harmful algal bloom neurological toxin in the drinking water at .058 ppb which is considered non-detect under the EPA recommended advisory levels of .30 ppb.
  • Samples collected on July 18th showed harmful algal bloom neurological toxin in the drinking water at .10 ppb which is considered non-detect under the EPA recommended advisory levels of .30 ppb.

The next sample date as recommended by the IEPA will be taken this Thursday, July 24th. The City will issue a formal update when we have the results from that sample.

WHAT ACTIONS HAS THE CITY OF MATTOON TAKEN TO CORRECT THE PROBLEM?

The City of Mattoon took the following actions to reduce harmful algal bloom neurological toxin levels:

  • Contracted with a consultant who recommended both short-term and long-term solutions.
  • Increased the Powder-Activated Carbon (PAC).
  • Increased chlorine feed rates.
  • Performed directional flushing of distribution system based on IEPA recommendations.
  • Developing long-term treatment options, including lake and plant treatment.