So far, Bay State legislature has earned a 'P' for procrastination

After weeks of dawdling, with a lot less to show for their efforts than most would care to concede, Massachusetts lawmakers are on an informal vacation. Technically, the Senate and House are still in session, with a few members coming in twice a week for sittings of less-than-a-yawn's duration. This meets the letter, if not the spirit, of the state constitution, which requires the legislature to assemble ''frequently'' from the time the annual session begins in January until formal adjournment.

The constitution provides for a full halt in operations for up to 30 days a year, and, during that period, legislators do not collect per diem expenses. But the session is not adjourned, and those who show up for the brief sittings or come to Beacon Hill on business, even for just a few minutes, are entitled to their travel allowances.

While it would be unfair to suggest that all state lawmakers prefer the current arrangement to a clean break in the legislative session, there was not even a whisper of dissent early July 11, when the decision to suspend formal sittings through Sept. 27 was announced by the leadership.

Senators and representatives were so anxious to hustle off that most of the year's more significant proposals, except for the fiscal 1985 state budget, were left languishing in various legislative pigeonholes.

Beyond the $8.15 billion spending authorizations for the 12 months that began July 1, state lawmakers spent most of the final pre-vacation days pushing through noncontro-versial measures, many of which could have been completed weeks earlier.

While such bursts of activity are common just before a recess or on the eve of adjournment, they are not without risks - including sloppy draftsmanship of measures.

This time was no exception. In fact, the lawmakers passed the wrong draft of legislation involving disbursement of medicaid funds, intended to provide free health care for 30,000 General Relief recipients. The flawed version was enacted by both the House and Senate, but the mistake was caught by the governor's office.

This mistake can be corrected (if it has not been already). During the past weeks, however, many low-income people have gone without free health care - which they would have been entitled to if the senators and representatives had enacted the right bill.

Each year, a few laws are enacted to correct major flaws in measures enacted in previous years. A lot of this extra work could be avoided if the language of each bill, before final approval, was checked to make sure the letter is in full agreement with the purpose. In the case of long pieces of legislation, different lawmakers could be responsible for review of specific sections. Such a procedure might lead to fewer bills gaining passage - and a more even flow of major measures onto the governor's desk.

Most of the legislation facing senators and representatives this fall is controversial, complex, and requires particular care. Included are all the proposals on the legislative shopping list of Gov. Michael S. Dukakis (D), including MassBank (a $300 million new agency to rebuild crumbling roads, bridges, and pipelines throughout the state).

Also high on the gubernatorial agenda is strengthening the state's public school systems; creating a water resources authority to construct and maintain water and sewer treatment facilities; providing a public authority to build and operate courthouses in the state; and revising the commonwealth's criminal sentencing structure.

While passage of any of these proposals is by no means assured, lawmaker votes may be easier to obtain after the Sept. 18 primary, when several lawmakers will face tough intraparty challenges for renomination.

Whether the governor succeeds in getting his proposals through the lawmaking thicket could depend on his ability to build support coalitions in the legislature as well as among interest groups and the public sector.

Municipal officials in some communities, for example, are eager to see improvements in the sewage-treatment facilities. But they are also concerned that the costs - which would be borne largely by local property owners - would be too great. Similarly, they are apprehensive over the potential financial impact of improvements of water lines.

Critics of MassBank question how well it would do the job and view it as a means of bypassing state and local agencies in favor of a new setup that may be replete with patronage.

The legislation, despite opposition from high-technology ranks, may have gone further if its boosters had done a better job promoting the idea outside lawmaking circles. If Mass-Bank fails to fly this year, it could leave Dukakis in the awkward position of having to recommend an increase in the state debt to finance a massive road, bridge, and public facilities reconstruction program.

It will also mean that John T. Driscoll, who the governor intends to head the agency, will remain at his $70,000-a-year post as chairman of the Massachusetts Turnpike Authority. And that complicates things politically; it's no secret that the top position at the authority is slated for state Sen. Allan R. McKinnon (D) of Weymouth, who is not seeking reelection this fall in anticipation of the appointment.

Legislative colleagues, even those who are not close to Mr. McKinnon, may find it difficult to reject MassBank knowing that a fellow lawmaker would be deprived of a job for which he is giving up his seat, a committee chairmanship, and a $45,000 annual salary.