A judge threw out a state board's decision to give a water permit to a large new dairy operation in southeastern South Dakota.
The proposed Hanson County Dairy would use an estimated 720,000 gallons of water a day. A number of county residents are protesting the operation.
Judge Sean O'Brien says South Dakota's Water Management Boarddidn't follow state law when it granted the permit.
He says the board didn't consider whether the local aquifer could supply the heavy water demand.
Now the water board will have to look at the issue again, or appeal O'Brien's ruling to the South Dakota Supreme Court.
An attorney for a citizens' group that opposes the dairy praised O'Brien's ruling Wednesday.