Mayor Walter E. Washington yesterday vetoed a City Council Bill serving the allegedly sub-standard D.C. General Hospital from the city's troubled Department of Human Resources.The mayor said the Council lacks sufficient information to justify the measure.

Council leaders predicted an override of the mayor's veto. The measure was passed unanimously on Dec. 17. A two-thirds majority of the members voting is needed to override.

Council chairman Sterling Tucker said, however, he will ask members to defer action on the veto until Feb. 8 in order to "prepare a carefully constituted rationale" for an override before the measure goes to President Carter.

Any Council override of a veto by the mayor must be sent to the President. Unless he disapproves such Council action within 30 days, the bill becomes law.

In a related matter, D.C. General's executive director, Robert B. Johnson, has noted as a "serious setback" the loss of 142 staff positions at the hospital as required under a city personnel ceiling. The reduction could permanently impair the ability to improve D.C. General, Johnson said in a report filed under a federal court order to upgrade the facility.

In his five-page veto message, the mayor said services at the hospital are improving despite its repeated failures to gain accreditation, most recently last week.

The mayor said it would be premature to place D.C. General under an independent, 11-member commission, as the bill provides, because he has established a special panel, announced last week, to study the over-all DHR function and structure.

The veto message also included four serious major objections" to the measure from acting DHR director Albert P. Russo:

It would "fracture the publicly funded health delivery system," by decreasing control over tax dollars that also pay for other city health facilities.

The hospital would have to concentrate more on its earnings from patient care, rather than providing health services regardless of ability to pay, and thus become more like a private facility.

Removal of $12 million in Medicaid payments generated by D.C. General from a central fund would strap the city's ability to pay for care elsewhere and require higher taxes or reduced patient services.

The bill inadequately provides for support services to the hospital, overstaffing some areas and ignoring others such as computer support and legal affairs, which are now provided by DHR. DHR would be incapable of giving support services to mental health, alcoholism and other programs located at the hospital, Russo said.

The mayor cautioned the Council to consider New York City's similar action six years ago, creating an independent hospitals corporation. That board has circumvented financial controls and lost the city $50 million, he said.

Mayor Washington urged the Council to await the findings of the special panel on DHR reorganization "before embarking on a proposal that will . . . prove difficult if not impossible to reverse."