All but two of the 17 states that joined in the lawsuit have Democratic governors. The exceptions are Maryland and Massachusetts.

The intensifying court fight could well be a long one. Larry Liebesman, a senior adviser with water-resources consultancy Dawson & Associates, predicts that a large number of industry groups and other interested parties likely will get involved as the process goes on.

Moreover, whichever side loses in the various district courts is likely to appeal.

Liebesman, a former long-time trial attorney in the Justice Dept.'s Environment and Natural Resources Division, says, "This is definitely a Pandora's box. There's no doubt about it."

Complicating the landscape further, the New Mexico Cattle Growers' Association has filed a lawsuit in yet another district court. That challenge takes a different angle from the states' and environmentalists'. It contends the new rule still sets too wide a regulatory reach.

Rule's effective date

The states' and environmentalists' lawsuits seek to undo the navigable-waters rule, which the Environmental Protection Agency and U.S. Army Corps of Engineers published on April 21.

The rule, which greatly tightens the scope of what the Clean Water Act terms federally regulated “waters of the United States," will take effect on June 22—unless the courts rule to reject or block it.

The regulation is important to construction companies because it determines in which locations near wetlands and streams builders need to get a federal permit before they begin work.

Construction groups welcomed the Trump administration regulation. Among other things, it says that wetlands, lakes and ponds are not waters of the U.S. unless they directly touch other federally regulated waters. It also would remove from federal jurisdiction “ephemeral” streams, which flow only after rains or snow fall.

An EPA spokesperson said in a statement emailed on April 30—before the states' filing but after the environmentalists'—that the agency "does not comment on specific litigation."

But she added, "EPA and the Dept. of the Army believe that the Navigable Waters Protection Rule will stand the test of time as it is securely grounded in the text of the Clean Water Act and is supported by legislative history and Supreme Court case law."

In their complaint, the states—joined by New York City and other agencies from California and North Carolina, are seeking to have the regulation vacated and set aside. California Attorney General Xavier Becerra said in a statement, "We don't intend to turn back the clock on clean waters. We'll prove that in court."

Environmentalists' lawsuits

The Annapolis-based Chesapeake Bay Foundation was first to move in the new round of litigation. On April 27, the foundation, with Shorerivers, another Maryland conservation organization, filed two lawsuits in federal district court in Baltimore.

One of the foundation's lawsuits seeks to have the court enjoin and vacate the new EPA-Corps rule. The other challenges an earlier Trump administration action to repeal a 2015 Obama administration Waters of the U.S. regulation, which embodied a much broader federal regulatory stance than the new EPA-Corps rule.

The foundation and Shorerivers explain they took the two-lawsuit approach because “the regulatory records are distinct and the standards for repealing an existing regulation and promulgating a new regulation differ.”

On April 29, other coalitions of environmental groups filed lawsuits in Charleston, S.C., and in Boston against the new navigable-waters regulation, contending that it violates the Administrative Procedure and Clean Water acts.

Blan Holman, senior attorney with the Southern Environmental Law Center, the lead plaintiff in the South Carolina case, said in a statement, “This unlawful rule puts the water used by hundreds of millions of Americans for drinking, bathing, fishing and business at risk as well as countless communities that deal with floods and hurricanes.

SCOTUS effect

Jon Devine, a senior attorney with the Natural Resources Defense Council—a plaintiff in the lawsuit filed in Boston—said the filings in multiple venues aren’t unusual for cases dealing with the scope of federal clean water authority.

Devine points out that in 2018, the U.S. Supreme Court ruled that challenges to the Obama Waters of the U.S. regulation had to originate in district courts, not in a single federal court of appeals.

Story updated on 5/1/2020 with EPA comment, states' lawsuit.