Since 2004, the Matteson Lake Association has funded annual studies to monitor the quality of water in Matteson Lake and its surrounding watershed. We are concerned about water clarity, bacteria, eutrophication resulting from excess nutrients, algal blooms, invasive weeds (including Eurasian watermilfoil), and a lack of diversity among aquatic plants populating the lake. Like so many other lakes in southern Michigan, the slow deterioration of these water quality indicators over many years can detract from everyone’s ability to enjoy a healthy, swimmable, fishable lake. Together, members of our Water Quality Committee sample the waters of Matteson Lake and its surrounding watershed for nutrient (total nitrogen and phosphorous) concentrations, total suspended solids, and E. coli bacteria. We also measure temperature, dissolved oxygen, and pH profiles as a function of depth near the center of the lake. In addition, we compare the quality of water flowing into Matteson Lake under the M-86 bridge on Colon Road to waters in the lake and exiting the lake over the dam on Butz Road. The Trophic State Index (TSI) combines three separate water quality measures: phosphorous concentration, green algae abundance, and water clarity. We think of this as our Lake’s report card, where lower values are better than higher ones. Since we began testing in 2004, Matteson Lake transitioned from mesotrophic to eutrophic conditions, with the TSI value peaking in 2010. Since 2014, we have been stable, but eutrophic conditions still continue. The overall goal of the Water Quality Committee is to return Matteson Lake to mesotrophic conditions. This will require sustained cooperation from Matteson Lake property owners and implementation of best agricultural practices in the surrounding watershed. The water quality reports below include data on E. coli testing. For a summary of Michigan’s E. coli water quality standard, see https://www.michigan.gov/egle/-/media/Project/Websites/egle/Documents/Programs/WRD/GLWARM/TMDL-Ecoli/ecoli-water-quality-standard.pdf Water Quality Reports 2024 Matteson Lake Water Quality Summary 2023 Matteson Lake Water Quality Summary 2022 Matteson Lake Water Quality Summary 2021 Matteson Lake Water Quality Summary 2020 Matteson Lake Water Quality Report 2019 Matteson Lake Water Quality Summary 2018 Matteson Lake Water Quality Summary 2017 Matteson Lake Water Quality Summary 2016 Matteson Lake Water Quality Summary 2016 Matteson Lake Aquatic Vegetation Study 2015 Matteson Lake Water Quality Report