For the District of Columbia government, 30 days can last as long as seven months. City officials want Congress to pass a law changing that.

This unusual situation in which the calendar is stretched beyond recogniton involves the time period during which measures passed by the City Council must "lay over" on Capitol Hill before taking effect as permanent District laws.

Under language Congress wrote into the city's Home Rule Charter, which went into effect in 1975, the national lawmakers themselves 30 legislative days in which to review each piece of local legislation.

During that review period, Congress has power to pass a resolution disapproving any piece of legislation. It never has done so.

City Council Chairman Sterling Tucker and Mayor Walter E. Washington's legislative assistant, Judith Rogers, told a House District subcommittee at a hearing last week that the definition of 30 legislative days has wreaked havoc on the city's ability to maintain as orderly lawmaking process.

By definition, both testified, a legislative day is one in which both the Housr and the Senate are in session. If one chamber is meeting and the other is not, it doesn't count as a legislative day. When weekends and congressional recesses are included, it takes at least two months - and usually longer - for 30 legislative days to pass and for permanent District laws to go into effect.

Because of this, the council frequently resorts to passing on an emergency basis, bills identical to those passed on a regular basis. An emergency bill remains in effect for 90 calendar days and does not have to lay over in Congress.

A White House task force recommended last fall that the charter's language be made more specific, perhaps by giving Congress 60 calendar days to review permanent city legislation. Last week's hearing was on a bill designed to carry out the task force recommendation.

Tucker testified that, in the most extreme case to date, it took even months for a District law to go into effect. The measure, passed by the council on July 20, 1976, restricted the conversion of apartment buildings into condominiums.

After the council's paperwork on that bill was completed. Tucker recounted, the enacted bill "was forwarded to the mayor on Aug. 12, 1976. The mayor approved the measure and returned it (to the council) on Aug. 26.

"Because Congress recessed during August, I delayed submission of the act to Congress until Sept. 15, 1976," Tucker continued. "Congress adjourned (for the year) on Oct. 1 and the act did not complete its 30 legislative day review period before those adjourments.

"In accordance with a ruling by the House parliamentarian, we resubmitted the act on the 10th of January, 1977. Thirty legislative days later, March 25, 1977, the act took effect.

"In sum, it took seven months for that act to become effective after the mayor's approval. Unfortunately, the condominium measure is not the exception," Tucker said.

During the protracted review period, the conversion of apartments to condominiums was blocked by a series of emergency bills.

Tucker said the uncertainty of the review period on permanent legislation causes widespread confusion and rings repeated inquiries from the public and from city officials on the effective dates of legislation.

"In many cases we are unable to make such predictions with any degree of accuracy," Tucker said. "We count our legislative days by simply referring to the Congressional Record. Otherwise we would have no official way of knowing if Congress - both houses - met when it was scheduled to meet."

Council passage of stop-gap emergency legislation to fill such legislative gaps has become almost routine.

As of last week, 79 emergency bills had been passed during the 1977-78 council session, and 14 more were scheduled for action Tuesday night. All 14 bills extended the effectiveness of emergency bills passed earlier. The extensions were made necessary because the effectiveness of permanent legislation was held up by the congressional Christmas recess.

Both Tucker and Rogers testified that they would prefer to see congressional review of city legislation eliminated. They noted that Congress still has power to override city council bills by passing its own laws.

Lacking outright elimination of congressional review, they urged that the time period be changed to a specific number of calendar days, except when Congress is out of session for an extended period.

Both officials said they would prefer 30 or 45 days, a period shorter than the 60 days advocated by the White House task force.

The officials also asked Congress to change provisions of the charter involving the mayor's vetoes of council bills.

Under the charter, a bill vetoed by the mayor and reenacted by the council is detoured to the White House where the president has 30 days in which to decide whether or not to sustain the veto. If the presidents sides with the bill then goes to Congress for its review.

Tucker and Rogers both asked that the presidential review be deleted.

Rogers requested, however, that the charter section dealing with council votes to override mayoral vetoes be changed. At present, the 13-member council can override a mayoral veto if two-thirds of the council members who are present and voting cast their votes against the mayor.

Because a council quorum is seven members and not everyone present is required to vote, Rogers said it is possible for fewer than five council members to override a mayoral veto.

"This is more troubling if the presidential-mayoral veto review procedure is eliminated," Rogers said.

She asked that the votes of at least three-fourths of the entire council membership, or 10, be required to override a veto. Such a large vote is neede, she said, because the council is a one-chamber legislature, unlike the two-chamber legislature general assemblies of Maryland and Virginia in which both bodies must vote to override a veto.

Action by the House subcommittee on the pending legislation was postponed.