Water levels, locations, depths, and aquifers tapped are given for 108 observation wells. Tabulated data include a listing of ground-water reports in Michigan, extremes of water levels for calendar year 1989 and for the period of record, pumpage of most major ground-water users in the State, and water-quality data from selected wells. In 1989, the two largest municipal users of ground water were Lansing and Kalamazoo. Lansing pumped 7.2 billion gallons from the Saginaw Formation and glacial deposits; Kalamazoo pumped 6.7 billion gallons from glacial deposits only.