DES MOINES, Iowa — Some of Iowa’s most powerful interest groups along with environmental organizations are backing efforts to clean up the state’s waterways, but there isn’t unity about how to take action on an issue that has frustrated lawmakers in the past.

Spurred by a Des Moines water agency’s lawsuit that blames upstream counties for polluted drinking water, there are several ideas for improving Iowa’s streams and lakes, however Gov. Terry Branstad has rejected two of the most prominent suggestions.

Although the lack of action is frustrating, it reflects the complexity of the problem and possible solutions, said Diane Rosenberg, who heads Jefferson County Farmers & Neighbors, one of 20 groups that have joined a coalition seeking a statewide moratorium on new and expanded livestock confinement operations.

“We need to look at who should be paying for our water cleanup,” she said. “There are a lot of people who argue where that responsibility falls.”

The powerful Iowa Farm Bureau also has weighed in on the issue, passing a resolution earlier this month that supported using new and existing state revenue to pay for water quality improvements.

Separately, Iowa’s Water and Land Legacy — a coalition of agriculture, business and conservation groups including the Iowa Soybean Association — called for raising the state’s sales tax by three-eighths of a penny for water quality and other natural resources programs. Their push follows failed efforts in the Legislature to add money to a natural resources and outdoor recreation trust fund created in 2010 but which still has no funding.

Apart from the state efforts, last month, a national group called the Midwest Row Crop Collaborative announced its plans to add sustainable farming practices in Illinois, Iowa and Nebraska and to reduce excessive nutrients from the waters that enter the Mississippi River. The group’s founding members include Monsanto, PepsiCo and Wal-Mart.

Branstad’s spokesman, Ben Hammes, said in an email the governor continues to believe long-term funding for water quality initiatives can be found “without raising taxes on Iowa taxpayers.” Branstad also rejected calls for the confinement moratorium, proposed by the Iowa Alliance for Responsible Agriculture, calling it an “extreme proposal that would harm agriculture and our economy in Iowa.”

Kirk Leeds, CEO of the Iowa Soybean Association, noted his organization supported the governor’s failed proposal last session to redirect some education infrastructure money toward water improvements. Leeds said the association is open to such discussions, but he doubts lawmakers would agree to use existing state dollars instead of generating new funding.

“You pit people against each other,” he said. “Are you going to reduce school funding? Are we going to reduce support for medical services? Where’s those dollars going to come from? And that’s where many of us have come to the conclusion that if we’re really serious about finding a long-term dedicated funding stream … that’s why the three-eighths cent sales tax makes sense.”

Rosenberg said members of the Iowa Alliance for Responsible Agriculture weren’t surprised by Branstad’s reaction to the group’s proposed moratorium on confinements, which they blame for polluting waterways and creating health problems for nearby residents. By publicizing the proposal, however, the group hopes to ensure water quality becomes an issue in the 2018 gubernatorial election.

“We don’t have any anticipation that Gov. Branstad will be supportive of this moratorium, but that doesn’t mean that others down the road won’t be open,” she said.

Although Branstad’s plan last session to redirect some education infrastructure money toward water quality was rejected by lawmakers from both parties, he has begun promoting a revamped version. Branstad also still supports legislation passed in the Republican-controlled House that would use existing state dollars for water quality. It did not advance in the Democratic-majority Senate over objections to using money from the state general fund.

Neither House Republicans nor Senate Democrats, who control those chambers, have endorsed a specific water quality plan for the next session.

A key motivation to the water quality debate has been a pending lawsuit by Des Moines Water Works, which supplies drinking water to 500,000 central Iowa residents. The utility, which has joined the Iowa Alliance for Responsible Agriculture, has challenged whether agriculture drainage districts have immunity from lawsuits and whether monetary damages can be sought. The Iowa Supreme Court is now reviewing the case.

Des Moines Water Works CEO Bill Stowe called the lawsuit a catalyst for broader discussions on water quality in the Legislature. He is still considering what legislation to back during the session but expressed confidence the uncertainty surrounding the lawsuit “will continue to keep the discussion going at the General Assembly level.”