A ten-year drought has greatly diminished the primary aquifer in the State of

East Carolina. In 2010, the State passes a regulation to deal with overuse of

water by existing land owners. The new law limits existing well owners to

pumping no more than 25,000 gallons of groundwater a day, no matter how

much water they had previously been using.

Fiona is a farmer in East Carolina. Her family has been using roughly

100,000 gallons of groundwater a day since the late 1800s for irrigating the

family farm. During this time, her neighbors have never complained about

her water use. Fiona continues to use 100,000 gallons of water, and the

government sues.

What arguments can Fiona make that she should not have to reduce her

water consumption, and what arguments can the State raise in response?

Who should prevail and why?