This graphic compares one of Grand Lake’s worst years for microcystin levels (2015) with the most recent full year of data (2025), demonstrating the progress made over the past decade.
This didn’t happen by accident. It reflects a sustained, coordinated effort by many individuals, organizations, and partners working together to improve water quality.
While microcystin levels have decreased over the past 10 years – and the data shows that our efforts are working – there is still much more to do. Toxin levels are not yet consistently below WHO and US EPA guidelines throughout the entire year, making it critical that we continue to pursue water quality. Now is the time to double down.
Note: This graphic differs from the one we typically share, which compares long-term historical microcystin averages to current levels. View that graphic here.
Thank you to Dr. Stephen Jacquemin of Wright State University–Lake Campus for compiling and presenting this data.