In terms of secrecy, Capitol Hill has traditionally been a leaky sieve, one of the few power centers in which the combination of partisan competition, conflicting special interests, political ambition and staff envy produce more information than the news media can consume.

This unofficial -- critics would say often illegal or unethical -- House and Senate function of providing information about and insight into the private workings of government increasingly provokes official response.

Lawmakers on Capitol Hill are conducting investigations of news leaks, paralleling a long history of executive branch -- particularly White House -- investigations of unauthorized disclosures.

Most recently, the House Committee on Standards of Official Conduct (the ethics committee) has issued a questionnaire to all members of the House Judiciary Committee staff in an attempt to find out who leaked a highly controversial committee report. The report accused former employes of the Environmental Protection Agency of giving "false and misleading" testimony.

The questionnaire orders the staff "to refrain from making known to any person . . . the existence of these questions." In classic Hill staff tradition, this demand for secrecy was promptly defied by sources who disputed the ethics committee's authority under House rules to impose a blanket of secrecy on its own questionnaire.

The inquiry was prompted by a story in The Washington Post last Nov. 16. Two other recent Capitol Hill leak investigations have involved stories in The Washington Times.

In one of those cases, the Senate Judiciary Committee has asked for a probe by the Federal Bureau of Investigation. In the other, the House ethics committee, after much debate, decided against trying to subpoena a reporter's notes.

The November Post story disclosed the existence of "a draft summary of a confidential House Judiciary Committee report" containing charges that "senior [EPA] officials gave 'false and misleading' documents and testimony to Congress."

In the questionnaire to the Judiciary Committee staff, the ethics committee asked for written responses to eight questions, including:

*"Have you contacted, or been contacted by, anyone from the news media regarding the report, the summary, or the contents thereof?"

*"Do you have any knowledge of any disclosure of the report . . . other than [to] committee members and authorized committee staff?"

*"Are you acquainted with or have you ever talked with any of the following individuals?" Eight reporters were listed -- Mary Thornton and Howard Kurtz of The Post, three on the Los Angeles Times, and one each at United Press International, The New York Times and Congressional Quarterly.

*"What is your relationship with such person(s) and the substance of your discussion with them?"

Staffers with questions about the questionnaire were advised to contact John M.S. Hoefer, ethics committee counsel. To a press inquiry about the questionnaire, Hoefer replied: "I'm not going to comment on anything this committee is doing . . . . I'm not willing to discuss anything."

Hoefer, however, did not feel constrained from inquiring who disclosed the existence of the questionnaire.

In the Senate's recent inquiry, Mark Godwin, spokesman for Judiciary Committee Chairman Strom Thurmond (R-S.C.), said Thurmond "requested that the FBI investigate the leak of classified material" to The Washington Times concerning the nomination of Stanley Sporkin, former general counsel of the Central Intelligence Agency, to a federal judgeship.

The story involved classified data disclosed by another CIA employe, an issue that held up Senate approval of Sporkin's nomination for 17 months.

The Times notes case was the most serious recent confrontation between a congressional committee and the press. It developed in late 1984, when the House ethics committee sought to discover how a reporter obtained results of a secret investigation into the finances of Democratic vice presidential nominee Geraldine A. Ferraro.

The committee dropped the subpoena after major news organizations protested the attempt as a threat to First Amendment guarantees of press freedom.