The Ban on Diversions and the Compact Council: How the Great Lakes Compact Governs Water Use

The Colorado River Compact of 1922 governs the American Southwest by dividing a river into specific consumption quotas for each state, a structure that ultimately incentivized the basin's chronic overallocation. The Great Lakes-St. Lawrence River Basin Water Resources Compact operates on the exact opposite premise: rather than dividing the water into shares, it establishes a nearly absolute legal wall around the watershed, banning the diversion of water outside the basin's natural hydrologic boundaries.[5]

Ratified in 2008 by eight U.S. states and codified in federal law, the Compact treats the Great Lakes not as a reservoir to be tapped, but as a closed ecological loop. The system contains roughly 20 percent of the world's surface freshwater, yet less than 1 percent of it is renewed annually by precipitation and groundwater flow.

The central mechanism of the Compact is its prohibition on new or increased diversions. According to the Ohio Department of Natural Resources, "The Compact prohibits new or increased diversions of water outside the Great Lakes Basin with limited exceptions," ensuring that water drawn from the basin remains within it to maintain the delicate balance of the ecosystem.[2]

The legal framework is administered by the Great Lakes-St. Lawrence River Basin Water Resources Council, commonly known as the Compact Council. Comprising the governors of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin, the Council holds absolute authority over any proposed exceptions.

The ban on diversions is not entirely absolute; the Compact outlines strictly defined exceptions for "straddling communities" and communities within "straddling counties." A straddling community is a municipality whose political boundaries intersect the hydrologic divide of the basin, meaning part of the town sits inside the watershed and part sits outside.[2]

For these specific municipalities, the Compact allows applications to divert water, provided they meet a rigorous standard of review. The most critical condition is the "return flow" requirement: the community must treat the water after use and pump it back into the Great Lakes basin, minimizing net loss to the system.[4]

The standard of review also mandates that the applicant demonstrate that no viable alternative water supply exists outside the basin. Furthermore, the diversion must not endanger the integrity of the Great Lakes ecosystem, a threshold evaluated by technical advisors from all member states and the two parallel Canadian provinces, Ontario and Quebec.[1]

The most prominent test of this exception mechanism occurred in 2016, when the city of Waukesha, Wisconsin, applied for a diversion. Located in a straddling county just miles outside the basin divide, Waukesha faced severe radium contamination in its deep aquifer and sought to draw up to 8.2 million gallons per day from Lake Michigan.[5]

The Waukesha application triggered the Compact's requirement for unanimous approval by the Compact Council. After years of technical review and intense regional debate, the governors voted 8-0 to approve the diversion, but only after reducing the requested volume and tightening the return flow stipulations to ensure the water was treated and returned via the Root River.[5]

The unanimous vote requirement serves as a structural veto, granting any single state the power to block a diversion. This design forces consensus and prevents a majority of states from colluding to export water at the expense of a minority, locking the governance structure into a defensive posture.

While the Compact Council governs the U.S. states, the broader Great Lakes-St. Lawrence River Basin Sustainable Water Resources Agreement includes Ontario and Quebec. According to the Food and Agriculture Organization of the United Nations, this parallel agreement ensures that the entire hydrologic system is managed cooperatively across the international border, preventing unilateral extraction by either nation.[1]

Climate change introduces new pressures on the Compact's framework. The Alliance for the Great Lakes noted in 2020 that shifting precipitation patterns and rising temperatures could alter the basin's water levels, making the strict conservation mandates of the Compact even more critical as evaporation rates increase.[3]

The Compact also requires each member state to implement its own water conservation and efficiency programs. The Commonwealth of Pennsylvania, for instance, mandates registration and reporting for any facility withdrawing more than 10,000 gallons per day over a 30-day average, ensuring granular tracking of water use within its borders.[4]

These state-level programs are subject to periodic review by the Compact Council to ensure regional consistency. This decentralized enforcement allows states to tailor their regulations to local industries—such as agriculture or manufacturing—while adhering to the basin-wide standard of preventing ecological degradation.[2]

The structural integrity of the Compact relies on its definition of the basin as a hydrologic reality rather than a political convenience. By tethering water rights to the physical flow of gravity rather than state lines, the agreement insulates the Great Lakes from the demands of distant, arid regions.[5]

As water scarcity intensifies globally, the Great Lakes Compact stands as a definitive legal barrier against large-scale water exportation. The mechanism holds because the eight states and two provinces recognize that their shared economic and ecological future depends entirely on keeping the water exactly where it is.