Eight AGs Filed Amicus Brief at Supreme Court in ‘Mississippi v. Tennessee’ Interstate Water Case

Colorado Attorney General Phil Weiser led eight attorneys general in filing an amicus brief urging the Supreme Court to reject Mississippi’s claims that Tennessee interfered with its authority by pumping groundwater out of an interstate aquifer. Mississippi alleges that groundwater is not a shared resource, so is not governed by the same rules as interstate rivers and streams. On November 22, 2021, the Supreme Court issued a unanimous decision rejected Mississippi’s argument, confirming that equitable apportionment does apply to interstate groundwater.

• Documents: Amicus Brief
• Document Type: Briefs
• States: Colorado Idaho Nebraska North Carolina North Dakota Oregon South Dakota Wyoming
• Issues: Climate Adaptation & Resilience Cross-Cutting & Administrative Oceans and Water Policy Water Water Management
• Era: Non-Federal
• Outcome: Win
• Action Type: Litigation