The telephone number provided yesterday for the Health and Human Services Department's AIDS hotline is for out-of-town callers. Washington area residents should dial 646-8182.

The calls stack up six and seven deep on a typical afternoon with the Health and Human Services Department's AIDS hotline, where six specialists field questions on Acquired Immune Deficiency Syndrome from more than 8,000 callers a day.

"Things really pick up in the afternoon, when the West Coast wakes up," said staffer Shirley Barth. Calls are answered by personnel drawn from throughout HHS, including the Centers for Disease Control, the Food and Drug Administration and the National Institutes of Health.

To handle the flood of calls at the Humphrey Building, the agency recently expanded the telephone bank to eight lines and installed a small computer switching system to hold calls and parcel them out among hotline workers. The machine registers each call on a digital display and signals with a small flashing light when another call is waiting.

Before the computer was put in, "the bells just drove us crazy," one harried hotline operator said. "Things are a bit less frantic now, but we get a surge every time the newspapers or television say something new about AIDS," he said.

The number of calls has dropped some since the 13,000 that were logged each day when the lines opened the week of July 5.

"There's occasional foolishness on the line, a few nuisance calls, but it's died down," Barth said. "Sometimes it seems people call just to have someone to talk to. Lots of callers have questions about how AIDS is transmitted--we get frequent 'swimming pool' calls, for example. The answer to that is 'No, you can't' " get AIDS from being in a swimming pool.

But other calls come from people who are afraid they have contracted AIDS. These people are usually referred to local medical agencies. Callers seeking counseling, referrals or services often are given the number of another toll-free AIDS hotline, which makes medical referrals. Operated by the National Gay Task Force, it is staffed by homosexual volunteers in the group's New York headquarters.

Shelley Lengel, the official in charge of setting up the HHS hotline, said that she has received valuable advice from homosexual groups already operating referral services and that the agency keeps in contact with them.

Nearly 2,000 people have contracted AIDS since the first cases were identified in early 1981, and more than 700 of them have died. The disease, for which there is no known cure, suppresses the body's immune system, leaving the body vulnerable to fatal infections.

AIDS cases are being reported twice as often as they were six months ago, CDC said yesterday.

The HHS hotline--800-342-AIDS--operates around the clock, offering callers a three-minute recorded message about the disease. Callers between 8:30 a.m. and 5:30 p.m. weekdays first hear the tape, then are answered live.