Georgia has joined a lawsuit to block a water cleanup plan for the Chesapeake Bay, fearing that if the Obama administration is empowered three states away, it could flex its environmental muscles in Atlanta.

Attorney General Sam Olens this month joined 20 mostly Republican colleagues in filing a brief led by Kansas in support of the American Farm Bureau, which is trying to halt an agreement among the Environmental Protection Agency and the states in the Chesapeake Bay watershed on how to reduce pollution. The bay cuts through the eastern side of Maryland and Virginia, and its feeder waterways also come from the District of Columbia, Pennsylvania, New York, Delaware and West Virginia.

A worry in Georgia is that the agreement might pave the way for federal regulation that could burden agriculture, including the state’s poultry industry, and homebuilding.

The filing states that the agreement “invades States’ traditional control over land-use management, violates both the express terms of the (Clean Water Act) and Congress’s intent to preserve the very state rights EPA has trampled.”

The agreement proposes to reduce pollutants and get the bay up to federal clean-water standards by 2025. EPA prescribed a “pollution diet” for the states in 2010.

“I would say to Gov. (Nathan) Deal and Gen. Olens, come to our state and talk to the governor,” said William Baker, the president of the Maryland-based Chesapeake Bay Foundation, a nonprofit dedicated to cleaning up the famously polluted estuary that has promoted the EPA plan.

“Come have oysters and crabs with us. Come talk to people who are afraid to have their children swim after a heavy rain. … They have no idea, apparently, how cooperative and how well this process is working. They don’t have to do it in their state if they don’t want to. Apparently they don’t have to clean up their own backyards. But they don’t have any right to tell us what to do in our backyard.”

But the 21 states fear that the EPA will come into their backyards with water cleanup plans. The states’ legal filing calls the EPA “coercive” in getting the Chesapeake Bay states to sign on with the plan, though they did so voluntarily.

The filing specifically expresses concern that the massive Mississippi River watershed — which includes a small slice of North Georgia — could be next in line for EPA intervention.

While the EPA does have the authority to establish a maximum amount of allowable pollution, the 21 states argue the Clean Water Act does not give the agency the power to regulate individual pollutants from individual sources.

“It does tell you whether you can farm or not,” Danielle Quist, of the American Farm Bureau, said of the Chesapeake Bay agreement. “Because if you can’t add any more nitrogen or phosphorous to your land, you can’t farm there.”

A Deal spokesman said the governor’s office was not aware of the lawsuit.

Among the groups joining the suit on the Farm Bureau’s side is the National Chicken Council, and Georgia is the country’s biggest poultry state.

“It is difficult to speculate what the effects might be, but basically we believe that, consistent with the Clean Water Act, the state is in the best position to develop plans to meet federal water quality standards in cooperation with the federal government,” said Mike Giles of the Georgia Poultry Federation.

Homebuilders, also wary of more stringent land-use regulation, have joined in the litigation with the farm groups. Environmental groups sided with the EPA.

The Clean Water Act requires that waterways be safe to drink from and swim in, and gives the federal government authority to regulate primary sources of pollution such as sewage-treatment plants. Farms and construction sites that produce sediment runoff do not require federal permits, but the Chesapeake Bay agreement requires specific cleanup plans that would impose pollution limits on places like farms.

A federal judge in Pennsylvania upheld the plan last year. The Farm Bureau – newly joined by the states – is challenging the ruling in the U.S. Third Circuit Court of Appeals.

Judge Sylvia Rambo wrote, in upholding the agreement, that it “undertook significant efforts to preserve the framework of cooperative federalism, and that EPA did not unlawfully infringe on the Bay states’ rights because the CWA is an ‘all-encompassing’ and ‘comprehensive’ statute that envisions a strong federal role for ensuring pollution reduction.”

The Chesapeake Bay Foundation calculated that based on state records, 58 percent of Georgia’s rivers and streams and 30 percent of the lakes, ponds and reservoirs that were assessed by the state in 2010 were “impaired,” violating clean water guidelines and inviting federal scrutiny.

“The fact that Georgia’s Attorney General is joining with polluters in their fight to halt a major cleanup of the Chesapeake Bay should trouble any Georgian who cares about clean water,” said Jennette Gayer, director of Environment Georgia. “It does not bode well for Georgia’s lakes and rivers when our own Attorney General will not let other states work cooperatively with the EPA and each other to clean up their own waterways.”