It’s been more than 30 years since the U.S. Supreme Court declared that water is an article of commerce and that Nebraska’s attempts to prevent the export of “its” groundwater to neighboring Colorado violated the dormant Commerce Clause.[1] The high Court did not return directly to the issue until last week’s ruling in Tarrant Regional Water District v. Herrmann.[2] [3] This time, a unanimous Court ruled againt the would-be exporter--Texas--and its effort to diver a portion of the Kiamichi River from a point within neighboring Oklahoma..

The Court struck a blow to one of Texas’ largest water districts, which supplies the exploding populations of the state’s north central region including Fort Worth, Arlington, and Mansfield.[4] The ruling thwarted Tarrant’s attempt to obtain a permit from the Oklahoma Water Resources Board to divert 310,000 acre-feet from the relatively clean Kiamichi River upstreamfrom where it flows into the salty Red River. This would have been enough water to supply the annual water needs of some 300,000 Texas families.[5]

In a narrow opinion tied tightly to the specific facts of the case, the Court rejected both of Tarrant’s legal claims.[6] First, the Court determined that the congressionally approved Red River Compact[7] did not preempt Oklahoma’s water statutes that limited the export of water outside the state’s borders. In particular, the complex agreement among Texas, Oklahoma, Arkansas, and Louisiana that allocated the surface waters of the Red River and its tributaries among the four states failed to provide specific guidance on the cross-border rights sought by Tarrant. In light of such silence, the Court was unwilling to interfere with Oklahoma’s sovereignty by allowing the Texas agency to reach inside its borders and divert from its navigable waterways.[8] The Court concluded that the Compact did not create a “borderless common in which each of the four signatory States may cross each other’s boundaries to access a shared pool of water.”[9] The Court also noted that the cross-border diversions in this case would be prohibitively complex, especially in the absence of language in the Compact specifying how they would operate. Specifically, Oklahoma would face a “herculean task” in determining the amount of water it would be obligated to deliver to other states, and prioritizing applications from various states would result in a “jurisdictional and administrative quagmire.”[10]

Having determined that the Compact did not preempt state regulation of waters allocated under the Compact, the Court next considered whether application of state law to waters not covered by the Compact violated the dormant Commerce Clause.[11] The Court neatly disposed of this claim in the three final paragraphs of the 31-page slip opinion when it explained, “The Oklahoma water statutes cannot discriminate against interstate commerce with respect to unallocated waters because the Compact leaves no waters unallocated.”[12]

What is the likely impact of Tarrant on future interstate water disputes?

Despite the fact-specific context of the complicated Red River Compact, the unanimous Court clearly sympathized with Oklahoma’s desire to manage its own waters, free from outside interference—perhaps a signal that the Court is moving away from the quarter-century-old Sporhase decision.[13] Among other things, the Court: 

·  Described a state’s right to control water within its own boundaries as a “core state prerogative;”[14] and,

·  Reiterated that “as sovereign entities in our federal system, the States possess an ‘absolute right to all their navigable waters and the soils under them for their own common use.’” Thus, in cases where states relinquish this power, the Court “would expect a clear indication of such devolution, not inscrutable silence.”[15]

Equally important, the saga of Tarrant offers an important lesson for every state water agency: the cheapest drop of water is the drop we do not use.

Tarrant—and Texas—have been slow to appreciate that conservation saves both water and money. According to the U.S. Geological Survey, the average Texan used more than 137 gallons of water per day in 2005 (the most recent comprehensive data available), as compared to the average American’s use of 98 gallons daily.[16] In contrast, Oklahomans used less than the national average—about 85 gallons per day. Instead of matching its thriftier neighbor’s practices, Texas offered Oklahoma about $1 billion dollars for the right to import water from the Kiamichi River.[17] When that deal failed to materialize, Texas Governor Rick Perry issued an official proclamation declaring April 22-24, 2011 as Days of Prayer for Rain in the State of Texas.[18] When the rain gods declined to pick sides, Texas squandered about $6 million on the failed Tarrant litigation.[19]

Wouldn’t it have been smarter—and cheaper—for Texas to get control of its own water consumption before casting a covetous eye on the waters of 38%-more-frugal Oklahoma?

Finally, signs of hope are appearing. Last month, Governor Rick Perry signed a packet of water reforms, to take effect September 1, 2013. In addition to the typical provisions for water governance and funding for new water infrastructure and projects, House Bill 4 contains provisions to promote water conservation and innovative reuse.[20] Hopefully, this signals that Texas and Tarrant are moving beyond bluster and blunder to satisfy their water needs through sensible and efficient conservation practices.