On Monday, the U.S. Supreme Court announced it would review the scope of the Clean Water Act, possibly as soon as this summer. The court granted a petition to determine whether the U.S. Court of Appeals for the Ninth Circuit “set forth the proper test for determining whether wetlands are ‘waters of the United States’” under the Clean Water Act.

The case traces back to a long-running dispute between two Idaho landowners and the U.S. Environmental Protection Agency over an area of their property deemed wetlands by the agency. According to the landowners’ lawyer, the property lacks a surface water connection to any stream, creek, lake, or other water body, and they feel it shouldn’t be subject to federal regulation and permitting. The couple was victorious in 2012 when the high court ruled that they could challenge EPA’s compliance order requiring restoration of the purported wetlands. Although EPA withdrew the compliance order, the Ninth Circuit, however, issued a decision in August 2021 affirming EPA’s wetlands determination.

This SCOTUS case comes at an important time in WOTUS deliberations, as EPA is in the first step of its “2-Step” WOTUS rulemaking. The Biden administration is formally repealing the 2020 Trump-era Navigable Waters Protection Rule and proposing to go back to the WOTUS definition used before the 2015 changes by the Obama administration while making provisions for some Supreme Court rulings regarding WOTUS. EPA is currently holding a public comment period on the proposed “Step 1” WOTUS rule that ends Monday, Feb. 7. This Step 1 definition will be what the agencies use until their “Step 2” rule is finalized. Expected later this year, the Biden administration says the Step 2 rule will include a “durable” definition of WOTUS that will offer greater environmental protections than the 2020 rule without the legal issues of the 2015 rule.