Washingtonians are generally more satisfied with the city's public services than they were six and eight years ago, with the fire department getting the highest marks and street repairs the lowest, according to results of an American University poll released yesterday.

Only 28 percent of those polled said they were satisfied with the public school system, although that figure represents an increase over the 19 percent satisfaction rate in the last American University poll taken in 1976. The poll was sponsored by the university's School of Government and Public Administration, under the supervision of professor Robert Hitlin.

Since the university's first poll in 1974, the most noticeable increase in satisfaction was in public transportation, a change attributable to the opening and expansion of the Metro subway system, Hitlin said. But while Metro's expanded services have increased satisfaction, public streets have deteriorated in ranking, with 72 percent now saying they are not satisfied with streets.

A total of 241 District residents were asked whether they are satisfied with the quality of six public services. The same questions were asked in 1974 and 1976.

Here are the satisfaction ratings for each public service:

Fire department, 89 percent; police department, 72 percent; garbage collection, 69 percent; public transportation, 57 percent; public schools, 28 percent; and street maintenance and repairs, 24 percent.

The residents polled were interviewed by telephone and selected through random-digit dialing.