The Montgomery County Council has approved making Poolesville Junion-Senior High School a "community school" this fall by opening the entire facility, including the two gymassiums, cafeteria, library and auditorium, to community use.

The council has also tentatively approved the expenditure of an estimated $489,000 to construct an indoor public swimming pool at the facility.

The council action Monday followed a recommendation by County Executive James P. Gleason that the school be designated a community school beginning July, 1978, and that the swimming pool be eliminated from the project. Last month, the county's state legislative delegation effectively killed a $400,000 bond measure that would have funded part of the project from state funds.

After the council vote, council member Elizabeth Scull, a longtome advocate of the project, termed the vote "a triumph." But council member Dickran Hovsepain, who cast the only vote against the proposal, interrupted her, reminding her that the approval of the pool was tentative, and depended upon the county's financial shape after the state legislature adjorns in April.

Hovesepian said he voted against the measure to make the Poolesville the measure included the swimming pool, which he said the county cannot afford.

As approved by the council, the project is a pared down version of one proposed by Poolesville citizens more than two years ago. Under the plan, the project would consist of a public library attached to the school, but separate center connected to the school.

In addition to the 3,000 residents of Poolesville, it would have served 6,000 persons from more than a dozen communities in the western part of the county.

The projects had been estimated to cost $1.5 million in public funds. But last month, some Poolesville citizens proposed reducing the public expenditure to $715,000 by having the medical and social services center built privately and having county funds pay for construction of the library shell while the interior would be built by vocational high school students.

The residents had argued that a separate public library was needed because the public would not use an expanded version of the school library. They also said that the present health clinic was outmoded.

After the council action Monday, the Rev. Filbert Moore, one of the main Poolesville proponents of the center, termed the action "a positive step forward." But he also said he feared that it could eliminate the possibility of acommunity "life center."