John T. Hazel, Jr., a major Fairfax County developer who is a member of George Mason University's governing board, has been lobbying county government officials to support a controversial sewer project that would both benefit the university and increase the value of land Hazel owns.

Acting County Executive J. Hamilton Lambert said recently that Hazel urged his support of the project "three to five times." Lambert added that he did not believe Hazel's action violated state conflict-of-interest laws. "It's a judgment call," the county executive said.

Virginia law prohibits state officials - including members of the governing boards of state universities - from voting or "[participating] in any consideration" of a matter in which they have a financial interest.

Last December, Hazel abstained from the university board's vote endorsing the sewer project, which would permit the institution to begin development of its 200-acre west campus across Rte. 123 from the central campus.

But since that time, Lambert and Fairfax planning director Theodore J. Wessel said Hazel urged them to support the project during personal meetings and telephone calls.

"He urged the county to get involved," Lambert said. "He talked to me three to five times over the months in my office and on the telephone."

Wessel said: "He [Hazel] has lobbied for the project in meetings with me."

Hazel, reached by telephone, last night, said "absolutely not" when asked if he thought his role in the situation amounted to a conflict of interest.

"I have endorsed the project" in conversations with county officials, he said, "and I would have felt derelict if I had not done what I have done" for the university.

He said that approval of the sewer project would mean a savings of between $75,000 and $100,000 in state funds because he and other landowners would share the costs of the project.

Last week, Wessel prepared a postion paper for the Board of Supervisors reaffirming the county staff's support for the sewer project. The supervisors are scheduled to vote on the question today.

The extension of the sewer line and the contruction of a pumping station would open up George Mason's west campus to new construction by the university. It would also bring a sewer line to a 50-acre tract south of the west campus that Hazel has proposed dividing into 99 lots.

If the proposed North Farm development has to use septic systems, Hazel said last months, there would be space for only about 89 lots. "It's not a case of development or no development," he said at the time.

The entire project aroused controversy because previously the county had been on record as opposing the extension of sewer lines to the area of the west campus and other tracts south and west in the Pope Head Creek watershed.

The envionmentally sensitive area drains into the Occoquan Reservoir, the drinking water supply for more than 600,000 Northern Virginians.

Some planners feared that development in the watershed could lead to pollution from increased deposits of sediment and from storm water runoff - pollution that could eventually make its way into the reservoir.

Although Wessell and his staff recommended that the county approve the sewer project, the supporting material given to the board said that the university's plans "give rise to the question of whether the university needs to expand to the west campus now or ever."

But, unlike universities throughout the commonwealth and the nation that are retrenching in the face of static or declining student enrollments, George Mason has an ambitious plan for growth during the 1980s.

The university earlier this year won state approval to have a law school, and it is expanding its graduate program. George Mason officials say that the university's growth is being hastened by the continuing rapid growth of the Northern Virginia area around it.

To allay fears that extension of sewerage would increase development pressures, Hazel gave the county a written promise that he will not seek to develop his parcel at a density higher than permitted in the county's master plan. He said he would limit density to two dwelling units per acre.

But Supervisor Audrey Moore (D-Annandale) said she fears opening a sewer line to Hazel's land could subject the rest of the area watershed to increased development pressure.

The university's share of the anticipated $589,979 bill for the sewer extension project would be $340,419 under the plan worked out by Wessel.

Part of the remaining cost, under Wessel's plan, would be borne by Hazel and passed along to future residents of North Farm. Another portion of the cost would be paid by residents of an existing subdvision, Braddox - some of whom have signed a petition opposing the project.