The Illinois Volunteer Lake Monitoring Program began in 1981 and was administered by the Illinois Environmental Protection Agency's Division of Water Pollution Control. In 1981, 87 lakes were monitored. The number of lakes monitored nearly doubled by 1990. Volunteers were trained to measure water clarity using Secchi discs, total lake depth, and to record field observations of water color, suspended algae and sediment, aquatic weeds and odor. They were expected to monitor at least three sites on a chosen lake twice per month from May through October. The program remained active through 2019 and is currently suspended.