On Tuesday, governors of the eight Great Lakes states approved a precedent-setting request by a Wisconsin city to take water from one of the lakes. The request sparked months of controversy.
Here's a primer on the issue:
Why did Waukesha make the request? Wells in the fast-growing Milwaukee suburb are tainted with radium, a health hazard. The city looked to Lake Michigan as a solution.
Why is the request so unusual? According to an agreement signed by the eight states, only localities within the Great Lakes basin can draw water from the lakes. Waukesha lies outside the basin.
How does Waukesha qualify? The agreement has a loophole for cities located in a county that straddles the Great Lakes basin.
Why the controversy? According to the states' agreement, Waukesha must show that it has no alternative water source. Waukesha says it is out of options; environmentalists say the city did not try hard enough to find an alternative.
What's next? Some fear that the approval will lead to similar requests from water-poor regions far from the Great Lakes. And that could test the states' agreement, which is called the Great Lakes Compact.