A Prince George's County-owned hospital, built amid clamor about the great need for a facility in the area, has filled only about a third of its 236-bed capacity during its first year and has accumulated a deficit expected to cost county taxpayers $1 million.

In Fact, said a state health care planner and County Executive Lawrence J. Hogan, if the Greater Laurel-Belts-ville Hospital were proposed today, the answer would probably be no.

"Given what we know about the population out there, if there were no hospital there now, they would be hard-pressed to get a hospital of that scope built there or any hospital at all", said William Opfer, chief of Maryland's comprehensive health planning agency's certification program.

"If I were county executive at the time, I would never have built it, but I would not have built a lot of things," said Hogan.

In spite of evidence that the $23 million hospital is underused, its prospects have improved. In February and March, it operated at a profit for the first time since it opened a year ago this month. But the profit was too little to overcome anticipated operating losses.

A futuristic, four-story building at Contee and Van Dusen roads, the facility fell victim to a statistical surprise.

Planners see now what they couldn't see when the hospital was approved-that predicted leaps in population growth for the area were wrong. They did not forsee a sewer moratorium and a mild business recession in the mid-1970s, both of which slowed anticipated growth in the area, according to a consultant whose firm helped plan the hospital.

In addition, according to the consultant and an area health care planner, other new hospitals opened before the Laurel hospital did and existing hospitals in the area expanded to meet the need the Laurel hospital was supposed to fill.

Still, demand for the hospital's services has grown, according to officials.

"One day we had three people waiting for a bed in the emergency room and six physicians who had called in waiting for beds for their patients," said William A. Parker, the county hospital administrator. "We decided to open more beds."

Beds (the basic measure of hospital in-patient capacity) were increased from 87 to 103 at the end of February, still less than 50 percent the number for which the hospital is licensed.

While Laurel's available beds have been about 90 percent occupied in recent months, according to Parker, only 28 to 36 percent of its total capacity has been in use - far below the national average of 73.8 for fiscal 1977, and Maryland's average of 82.8 percent.

Even if the hospital does fill up and continues to make money, the county's budget director said he expects that the $1 million anticipated operating loss, which county residents have to make up in taxes, may not be repaid for some time.

"I don't think we can wipe out the whole deficit by the end of the year by a long shot, said Parker, "but in my opinion, it will be repaid over the long haul."

The county also advanced the hospital $2 million for startup costs last year and anticipated paying approximately $1 million in interest this year on money borrowed to build the hospital. However, the county expects the hospital to repay those costs eventually.

The hospital was approved in 1972 by the state's comprehensive health planning agency. The agency, shich was new, relied heavily on a consultant's report and approved it "on the basis of much heavier need" than materialized, said Opfer.

The consultant's report predicted that the hospital would be self-supporting, with occupancy increasing to 80 percent in the second year of operation.

The consultants, Block, McGibony and Associates of Silver Spring, relied on official population projections, primarily from the Maryland-National Capital Park and Planning Commission, in estimating need and predicting occupancy, said Mandell Bellmore, president of the firm.

Projections made in 1971, before 1970 census data were available, showed population in the area to be served by the Laurel hospital growing from 77,700 to 206,100 in 1980 and 270,700 in 1990. Updated projections in 1975 called for population in smaller area to grow only to 159,900 in 1980 and 210,200 in 1990. The service area was redifined to take into account other hospitals that opened in the county.

In 1977, estimates were revised downward again to 104,273 in 1980 and 149,656 in 1990.

Within about a year of approval for the Laurel hospital, meanwhile, four others were also approved, according to Bill Hicks, director of project review for the regional health planning agency that covers Prince George's County.

Two of these hospitals, Prince Geprge's Doctors (about nine miles away) and Southern Maryland (about 25 miles away) opened before Laurel and achieved about an 80 to 85 percent occupancy rate within about a year, said Hicks.

A third, a 200-bed hospital that would have opened about five miles down the road from Laurel, was never built. The fate of a fourth, planned for Bowie, is now in question and will depend, in part, on what happens at Laurel.

A key factor in the success of the Laurel hospital will be the willingness of doctors practising in the area to refer patients there. "It's a question of changing the pattern of practice for the physicians as well as for the community," said Parker.

"The doctors that were coming just once in awhile are coming more often now," said Felix Flores, a general surgeon who is head of the department of general surgery at Laurel and on the executive committee of the Prince George's County Medical Society.

"When patients ask me about quality, I say that the example I can give is that my daughter had surgery and she went to Laurel."