Knowledge and perceptions of Michigan residents about groundwater were assessed so that a comprehensive educational program could be developed and baseline information established to document the program's impact over time. Data were collected from 663 residents in urban, rural, and farm households. Results indicated that knowledge about groundwater was moderate and that a statewide educational campaign on facts about groundwater was necessary. People perceived that land use practices affected groundwater quality at the national, state, and county levels but not at their household level. Significant differences were found among urban, rural, and farm residents and between farmers and nonfarmers in their perceptions of the effects of land use on groundwater quality.