A proposal to house jail inmates, drug addicts, alcoholics and the homeless in a South Arlington neighborhood has become the most bitterly opposed local initiative in years, threatening the county's longtime reputation for building consensus between government and civic groups.

Two dozen civic associations have lined up to fight County Manager Anton S. Gardner's proposal for a $4.7 million residential treatment center.

Opponents say the site, near Barcroft Park, is inappropriate and they accuse Gardner and his staff of trying to rush the issue toward County Board approval without allowing sufficient community debate.

"I've never seen people so outraged," said John Brannock, president of the Claremont Citizens Association and an Arlington resident for six years. "For years there has been this sense of cooperation between the people and the county, and now people feel like the county is trying to put one over on them. There's a sense of betrayal."

The anger and bitterness that menace the civic spirit known fondly as "the Arlington way" were clear at a neighborhood meeting last week.

More than 350 people attended a Claremont neighborhood meeting to hear county staff members explain the proposal, one of 28 such meetings scheduled. The county representatives were heckled and booed by residents who fear the center would bring criminals and transients to the park, which is next to the center's proposed site on South Four Mile Run Drive.

"I don't want criminals in an area where there's children. And that's all I have to say about it," declared an elderly woman at another meeting in the Barcroft neighborhood this week.

The proposed 130-bed treatment center would include 70 beds for minimum-security prisoners, jailed for offenses such as shoplifting, drunken driving and possession of small amounts of drugs. The center also would have about 40 beds for the homeless and 20 beds for the county's first detoxification unit, which would offer three- to 14-day treatment programs for drug and alcohol abusers.

The inclusion of jail inmates at the center has drawn the most community opposition and put the proposal on a fast track for consideration by the County Board. The board is scheduled to take up the issue on June 23, about eight weeks after plans for the treatment center were announced.

Arlington officials are desperate to relieve crowding in the county's jail, which now holds about 400 inmates in space designed to hold 164. A new jail designed to hold 656 inmates isn't scheduled to be completed until 1992, and county sources say that Arlington officials believe a lawsuit against the county over jail crowding is likely.

Pat Henkel, president of the Northern Virginia chapter of the American Civil Liberties Union, said the group considers Arlington's jail conditions to be among the worst in the region, and she acknowledged that a lawsuit against the county is under "strong consideration."

Despite assurances from the county that security at the proposed treatment center would be tight, some neighbors said they fear criminals and transients from the facility would mix with children and others who play and jog in the park.

"People are scared as hell about this whole thing," said John Westgate, who lives in a condominium near Barcroft Park.

Westgate and other residents have distributed fliers throughout South Arlington, condemning the proposal. County officials have said the fliers, many of which refer to the corrections part of the proposed center as a "jail," are misleading.

"If I thought a truckload of thugs was going to be delivered to my neighborhood I'd be opposed to it too, but that's not part of the proposal," said County Board Chairman Albert C. Eisenberg.

Eisenberg said he believes residents will have enough time to make suggestions about the proposed center, and said they would be wrong to think that the board has already made up its mind to support it. "This is not a done deal," he said. "By the time this reaches the board, people will have had nearly eight weeks to comment on it. I think that's certainly enough time."

"The worst part of this may be a legacy of distrust," said Randy Swart, president of the Barcroft School and Civic League. "Some people down the Four Mile Run Valley may never feel the same way about this county's government again."