DECATUR – At the height of this year’s drought, decision-makers at the agribusiness giant Archers Daniels Midland kept an uneasy eye on the reservoir down the hill from their headquarters.

At one point, the water level fell to within 2 inches of the point where the company was in danger of being told for the first time ever that it couldn’t draw as much as it wanted. The company uses millions of gallons of water a day to turn corn and soybeans into everything from ethanol and cattle feed to cocoa and a sweetener used in soft drinks and many other foods.

Rain eventually lifted Lake Decatur’s level again. But the close call left ADM convinced that, like many Midwestern companies and the towns where they operate, it could no longer take an unrestricted water supply for granted, especially if drought becomes a more regular occurrence because of climate change or competition ramps up among water users.