Four out of 10 lawyers surveyed at Washington's largest firms did significantly less free legal work for the poor than even the minimal guidelines set by conferences of local lawyers and judges, according to a survey to be released this week by the Washington Council of Lawyers.

More than 40 percent of the approximately 800 lawyers surveyed did 20 or fewer hours of free work each year, even though local judges' voluntary guidelines call on them to put 40 hours a year into what the legal profession calls "pro bono" work.

The survey -- the first in the District to study the pro bono contribution of individual lawyers -- comes as federal support for legal services to the poor is lagging and there is a growing national debate on whether pro bono work should be mandatory. Several states, including Maryland, have considered mandatory proposals, but many lawyers have balked, and no state has adopted such a plan.

In the District, mandatory pro bono has not been formally proposed, but the bar's new code of ethics states that lawyers "should be guided" by the 40-hour annual minimum endorsed in the early 1980s by the judicial conferences of D.C. and federal judges.

"Here in Washington, where we have one of the best commitments to pro bono in the country, or at least think we do, it is surprising that there are so many lawyers who do nothing," said council President Paul M. Smith.

Smith said the survey also found that "the increasing pressure to bill more hours and keep the profit margins up" is discouraging lawyers from doing pro bono work. Generally, lawyers with the best records were with firms having policies that credit them for public service work in the same way as work for paying clients, the survey found.

The council received more than 800 responses from about 2,500 lawyers in the city's 60 largest firms, surveyed in April and May. It surveyed lawyers who had joined the D.C. Bar from 1979 to 1988, in an effort to reach associates and young partners. The study therefore did not include the firms' senior partners. Those who responded to the survey were promised confidentiality.

"We were trying to look at the people most affected by the official policies and practices of the firms, the associates and junior partners who are more subject to the power structure," said Susan Hoffman, who led the survey task force.

Those who responded with individual comments sounded this clear theme: There is often a disparity between a firm's official policy on pro bono and day-to-day practice.

"The stated policy is farcical," wrote one respondent, "in the face of pressure regarding billable hours," work for which clients pay.

Another lawyer wrote that his firm's policy was good, but not always followed. "One partner commented of pro bono activities: 'I practice law to make money. Can you think of another reason?' " this lawyer wrote.

Others wrote that their firms were interested only in high-profile pro bono work. My firm "cares only about large, sexy, publicity-engendering pro bono work, which partners handle," wrote one lawyer. "Work for indigent people . . . is tolerated, not encouraged."

Another wrote that there was no regard for "non-sexy pro bono, that is other than death penalty" cases. Another said he was told not to take politically sensitive cases.

One lawyer wrote that work for the poor was not considered "real work," and another wrote of "denigration by important partners" for doing pro bono cases.

Smith said it is clear from the survey and comments that policies encouraging pro bono "must be backed up in fact by giving people credit for the work they do."

He and Hoffman saw some good news in the survey, citing lawyers who said they exceed the 40-hour guideline. "Those who are committed seem to be very committed," said Hoffman. "They give more than twice the suggested guideline." The survey showed strong firm policies can work, Smith said.

Smith said that the survey may add fuel to the debate over mandatory pro bono, but that the council has no stated policy on the issue.

In Maryland, a proposal for mandatory pro bono work sparked an intensive campaign last year that greatly increased voluntary pro bono commitments. In New York, Chief Judge Sol Wachtler warned this year that he may make pro bono mandatory if lawyers do not respond voluntarily to the "dire need" for public service by 1992.

Although the council will not reveal the names of firms whose lawyers cited problems, it is offering to meet with partners to discuss the survey results.