The Supreme Court on Monday sided with Tennessee in a water dispute with Mississippi, ruling that the court should divide up the water that’s in an aquifer between the states to determine how much each can use.
In a unanimous decision, the high court rejected Mississippi’s attempt to get damages from Tennessee for pumping water from the resource.
Instead, the judges decided that waters should be governed by “equitable apportionment,” a process by which the court allocates how much of the water each state can use.
This process is often used in water disputes between two states, but the new ruling is the first time it is applied to an aquifer — where groundwater is held in rocks or sediment — that sits between two states.
The judges said that Mississippi is wrong to try to claim all of the groundwater that’s located underneath it since the waters flow between states.
“Mississippi’s ownership approach would allow an upstream State to completely cut off flow to a downstream one, a result contrary to our equitable apportionment jurisprudence,” said the opinion, which was penned by Chief Justice John Roberts.
The judges previously appeared skeptical of Mississippi’s claims during oral arguments last month. The state argued at the time that Tennessee was acting “extraterritorially” when it set up pumps near the states’ border to access water under Mississippi.
Asked for comment, a spokesperson for Mississippi’s attorney general’s office said via email, “We respect the decision of the Court.”