William D. Ruckelshaus, President Reagan's choice to head the troubled Environmental Protection Agency, will confer today with White House senior staff members about conditions under which he would accept the post, administration officials said yesterday.

If those terms are agreeable to the White House, the Ruckelshaus appointment could be made final today, but that is not certain. "Some things still have to be worked out," a White House official said.

Ruckelshaus, currently a senior vice president of the Weyerhaeuser Co. in Tacoma, Wash., arrived at National Airport last night, eluding reporters. Former Washington governor Dixy Lee Ray, also on the flight from Seattle, confirmed that he had been aboard and exited from the plane's back door shortly after it landed, UPI reported.

But before leaving Seattle, Ruckelshaus told CBS News, "He Reagan has asked me to consider this and I'm doing it. I don't think it's a matter of whether you want it or not, it's a question of whether you think you can be helpful in responding to the president's request."

He is not scheduled to see Reagan today, but a meeting may be arranged if his meeting with senior presidential aides results in an agreement to take the job, an administration official said.

On Friday, the White House asked Ruckelshaus, 50, to return to the EPA, where he served as the agency's first administrator from 1970 to 1973. Later that year, he resigned as deputy attorney general in the administration of President Richard M. Nixon rather than fire Watergate special prosecutor Archibald Cox.

Administration officials are looking to Ruckelshaus to restore credibility to the EPA in the wake of Administrator Anne M. Burford's resignation, and continuing congressional and FBI inquiries into charges of conflict of interest, political manipulation and mismanagement.

Before accepting the post, however, Ruckelshaus is expected to demand some independent authority, including the option to bring in some of his own deputies. He also is expected to discuss a way to separate himself from any EPA decisions affecting his current employer.

White House officials have said they would like to appoint a new deputy administrator at the same time, and a leading candidate is Walter C. Barber, who served as acting EPA administrator during the first months of the Reagan administration. The officials have said Reagan does not plan to keep John W. Hernandez Jr., the acting administrator.

Reagan, returning yesterday from Camp David, Md., refused comment, saying he would answer questions "in a few days" at a news conference.

Administration officials have said that they believe Ruckelshaus would be welcomed by Congress.

Yesterday, Dr. Samuel Epstein, a professor of occupational and environmental medicine at the University of Illinois Medical Center, said more than just a new administrator is required.

Speaking on "Face the Nation" CBS, WDVM , Epstein said that Ruckelshaus has "the most excellent reputation," but that "we do have some problems with him insofar has he has publicly defended the record of Reagan and Interior Secretary James G. Watt.