Calhoun Lake spans 619 acres with a maximum depth of 13 feet. Since monitoring began in 1999, the lake has maintained consistently strong water quality. Recent data shows positive trends in water clarity (Secchi depth) and a reduction in total suspended solids (TSS), indicating ongoing improvement. Throughout the open water season, Calhoun remains suitable for swimming and wading, thanks to clear waters and low algae levels. While the lake is currently classified as eutrophic, long-term trends suggest it's moving toward a healthier mesotrophic state.

Monitoring results highlight improvements in several key indicators of water quality, including total phosphorus, TSS, and chlorophyll-a. Notably, water clarity has significantly improved over time. Calhoun’s watershed features a mix of cultivated crops, pasture, grassland, forest, wetlands, and limited developed areas. These diverse land uses influence nutrient runoff and sediment flow, playing a key role in shaping the lake’s water quality. Overall, Calhoun Lake supports a thriving aquatic ecosystem and continues to show encouraging signs of long-term water quality improvement.