For all the scorn and derision rolling across the House floor this week, one would have thought a horned devil had taken a seat on the Democratic side of the aisle.

Rep. Robert W. Edgar (D-Pa.) is not only a devil, but a Methodist minister is his private life. But he has sinned mightily nevertheless, as the Houses sees it: he has attacked a public works bill

His brethern have reacted with unusual vitriol and emotion, which shows what can happen when a congressman tries to say nay on this subject, as Edgar has.

One member, Rep. Gene Snyder (R-Ky.), suggested Edgar had not "an ounce of milk of human kindness in his soul" in suggesting that some projects be excised from the bill.

Another,Rep. Tim Lee Carter (R-Ky.) although he apologized the next day, alluded snidely to Edgar's Methodist ministry and erroneously accused him of landing an unneeded courthouse for his district.

Rep. Carl D. Perkins (D-Ky.) said Edgar was threatening "the human rights of the people of the Appalachian region."

Kentuckians may say these things with more flair than some others, but the same feelings seem fairly widespread about Edgar's assault on the $4.4 billion water resources bill the House will take up again today.

The water resources bill, known sneeringly as the pork barrel, authorized flood-control dams, harbor dredging, navigation projects, marinas, bridges and roads.

This legislation, usually produced every election year, is one of the most popular that Congress deals with because it means projects for individual districts -- tangible proof that a legislator is at work.

But not in their wateriest fantasies could House members have dreamed up this year's version. The costliest ever, it would provide almost 200 projects around the country, affecting what President Carter said Tuesday would be 70 percent of the congressional districts.

Meeting with out-of-town editors, the president called the bill "very large and wasteful." While not using the word "veto," he said, "I intend to oppose these threats to our federal budget."

While Edgar and the White House are going in the same direction, ironically and not at all surprisingly, the congressman is doing most of the fighting and taking most of the heat. He has had little help from the administration.

The argument is over national water policy. Carter wants a new policy that he thinks would save both water and federal funds.

The House and Senate public works committees, which traditionally have had the water policy field all to themselves, view the presidential suggestions as a violation of congressional turf.

Turf actually is the name of the game, for as Edgar has found this week and during the past several years, individual members ar offended personally when a colleague questions a favored reservoir or marina project.

Edgar, a member of the governing committee, has forced debate on the bill by threating to call up 184 amendments each aimed at some members' favorite project.

"I believe many members with projects in the bill are saying, and they have told me privately, 'right on, Bob.' But they can't come out and oppose their own projects. It's just unfortunate that one can't raise policy issues apart from individual projects," Edgar said yesterday. "The criteria for all of these ought to be on their merit."

The environmental bloc, with which Edgar has been working, regards the congressman's performance as "extraordinary" in the words of Edward Osann, head of the Coalition for Water Project Review.

"The debate, the tone and direction of the votes indicate that the House generally is really hostile toward debating the merits of these issues," Osann said. "Their reaction to someone like Edgar is to exorcise, to banish him from the community of fraternal advancement."

By all rights, your typical politician would flinch at working himself into this kind of bind. But Edgar isn't typical, and, until he got elected "by accident" in 1974, he hadn't even been in politics.

Edgar, 36, was the Protestant chaplain at Drexel University and codirector of a community center before he decided to run for the House.

It really made no sense. His surburban district, southwest of Philadelphia, had elected Republicans without fail since 1858. He had no political pedigree.

"Until a year before the election, I had never been to a political meeting.

One of my assets is that I have no political background. My constituents elected me not to come down here and let it be business as usual," he said.

As a member of that reformist "Watergate" class of 1974, Edgar took it seriously and still does, unlike some of his classmates who have mellowed with time.

There's a reminder, maybe intentional, maybe not, hanging on the wall behind his desk. It's a reproduction of Picasso's Don Quixote, the man who used to joust at windmills. CAPTION: Picture, Rep. Robert Edgar: "Criteria for all of these [projects] ought to be on their merit." By James K. W. Atherton -- The Washington Post