Farmers are counting on the U.S. Supreme Court to clarify the extent of federal Clean Water Act authority now that the justices have agreed to revisit the controversial subject.

The nation’s highest court will review an Idaho lawsuit to determine which wetlands should be regulated as “waters of the U.S.” under that statute — a matter of longstanding legal debate.

“You’ve just had a lot of confusion in the courts over what is a regulable wetland,” said Damien Schiff, senior attorney with the Pacific Legal Foundation, a libertarian law firm. “Because of that confusion, the court was convinced to finally try again.”

The agriculture industry is strongly invested in the matter because farms that come under Clean Water Act jurisdiction must comply with expensive and time-consuming regulations or face steep penalties.

“At the end of the day, that does mean the cost of business goes up,” said Courtney Briggs, senior director of congressional relations with the American Farm Bureau Federation.

Under a revision to the “waters of the U.S.” definition proposed by the Biden administration, farmers would effectively need to hire lawyers and consultants to understand if their property is a regulated wetland, Briggs said.

“It creates a lot of uncertainty on the ground,” she said.

Technically, “prior converted cropland” that was cultivated before the Clean Water Act’s 1972 enactment cannot be regulated as a wetland.

In practice, though, the federal government has still required Clean Water Act permits for changes in agricultural crops and practices, Schiff said.

For example, the Pacific Legal Foundation has represented farms that tried switching from pastures to row crops or nut orchards, only to find out they’re subject to permitting regulations, he said.

The federal government is concerned about tillage of “vernal pools” that are dry most of the time but are still considered wetlands with a significant connection to a navigable waterway, Schiff said.

There’s a need for “bright line jurisdiction” over which wetlands are regulated, since the exemptions for farmers are so complex, Briggs said.

“Unfortunately these exclusions are very convoluted,” she said. “A farmer doesn’t have the certainty about whether it applies to them or not.”

In the lawsuit the Supreme Court decided to review on Jan. 24, Idaho landowners Michael and Chantell Sackett are challenging a finding that they need a Clean Water Act permit to build a house on their property. The federal government considers the parcel a regulated wetland, even though a road separates it from a nearby waterway.

The facts of the case make it an “excellent vehicle” to resolve uncertainties that have persisted since the highest court’s last Clean Water Act decision in 2006, known as Rapanos, according to the Pacific Legal Foundation.

“It’s been a dispute not just for the Sacketts but a broader legal dispute for a long time,” Schiff said.

In the 15 years since Rapanos, appellate courts haven’t been able to agree on how to apply the legal precedent, the PLF said in its petition to the Supreme Court. Meanwhile, federal agencies have repeatedly changed their interpretation of the case law.

In that time, Congress hasn’t attempted revising the Clean Water Act itself to dispel the uncertainty, he said. “The only government actor that can fix the problem is the court.”

The different composition of the Supreme Court gives hope that the Sackett case will create a legal precedent with a clear test for which wetlands are regulated, Schiff said.

Three justices confirmed during the Trump administration — Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett — are solid “textualists” who are likely to interpret the Clean Water Act as having a limited scope, he said.

As a practical matter, the Supreme Court’s willingness to review the case signals that the justices expect to achieve a majority opinion on the issue, Schiff said.

That’s important because the Rapanos case produced a “split decision” lacking a majority opinion, which has complicated the legal interpretation of wetlands jurisdiction in thorny circumstances, he said.

“It really couldn’t come up with a single test to cover those cases,” he said.

The U.S. Environmental Protection Agency urged the highest court against taking the Sackett case, arguing that the review would be premature.

Federal agencies are currently considering a new interpretation of the “waters of the U.S.” definition that draws on “the best available scientific evidence” and several decades of regulatory experience, the EPA said.

“That regulatory process should be allowed to play out before this Court revisits the scope of the agencies’ authority under the CWA,” the agency said.

Since the Supreme Court has decided to review the case, the federal government should postpone making the new regulations final, said Briggs of the American Farm Bureau Federation.

“It doesn’t make sense for the regulated community or the government to move forward with crafting a new rule when the road map has not been provided,” she said.