The $4 billion public works bill that is the heart of President Carter's economic stimulus package has been delayed for three weeks by a House-Senate dispute over water pollution.

The bill authorizing $4 billion in grants for quick-starting local public works projects ot create 160,000 jobs passed the House on Feb. 24. The Senate approved it on March 10 but added a two-year authorization of $9 billion in grants to help municipalities contrusts sewage treatments plants to help up with nation's waters.

The House, whose Public Works Committee wants to do a substantial rewriting of the water pollution control act rather than just vote more money for its, has refused to go to conference with the Senate to settle their differences.

House managers of the public works bill fear that is they permit water treatment funding to pass now in the public works bill they will have lost leverage to get action later on changes in the water treatment program. The Senate balked at House amendments last year and let a bill die in conference. House leaders have actively supported the refusal to got to conference until the Senate agrees to drop the water treatment money.

Sen. Edmund S. Muskie (D-Maine), who led the move to add the water treatment funds to the public works bill, accused the House yesterday of "strongarm tactics" in refusing even to sit down and talk with the Senate. House members have accused the Senate of holding the Presidents public works bill hostage in exchange for the warer treatment money.

The House will vote next week on a bill authorizing $17 billion in water treatment grants over three years and making various changes in the program. House leaders want the Senate to drop the water money from the jobs bill and include funds in separate comprehensive water treatment legislation.

Muskie said yesterday that his Clean Water subcommittee will make a comprehension study and produce legislation on the water pollution program later this year. But he said his subcommittee will not be able to act for some time and that meanwhile water treatment money is bodly needed. Thirty-four states, including his home state of Maine, already have or will by the end of summer run out of funds to build treatment plants, Muksie said.

Muskie said the water treatment money would produce 360,000 jobs and should be welcome as an economic stimulus. He suggested that a possible compromise would be a one-year, rather than two-year, funding of the water treatment program.

Sen. Jennings Randoloph (D-W. Va.), chairman of the parent Senate Publuc Works Committee, said he would get in touch with House leaders of ask if this would be enough to get the two houses into conference.

House Majority Leader Kim Wright (D-Tax.) told reporters the House might accept atopgap water treatment funding if the Senate in turn would accept a moratorium on some provisions in the program that the House bill would repeal Wright said only 9 per cent of the funds voted for the water treatment program between 1973 and 1975 were spent because the program "choked on its own red tape."

One of the most controversial provisions in the House Water treatment bill would overturn a 1975 court decision and restrict the authority of the Army Corps of Engineers to regulate disposal of dredged or fill material in the nation's waterways. Environmental groups strongly oppose this for fear the House bill's provision would weaken protection of wetlands, which are the spawning ground of fish and wildlife.