For those Northern Virginians who may be concerned about the high levels of chloroform - a suspected carcinogen - found in their drinking water, Virginia Health Department official Oscar Admas has a reassuring answer: "We don't see bodies laying in the gutter, so let's not panic."

Chloroform is formed in drinking water when chlorine, which is used as a disinfectant to kill bacteria causing infectious diseases like typhus, reacts with organic material that survives filtering. Like many other contaminants identified as suspected carcinogens (chemicals that have caused tumors in laboratory animals and are therefore considered potentially hazardous to humans), chloroform is measured by the billionth part.

The Environmental Protection Agency is considering rules that would limit the amount of chloroform in water to an amount not greater than 100 parts per billion - considerably lower than concentrations found in the Ocoquan Reservoir during 1975 and 1976. The reservoir operated by the Fairfax County Water Authority, serves about 600,000 Northern Virginians.

Adams, director of the state health department's engineering division, thinks substances measured to the billionth degree are mighty small, even if they are carcinogens.

Appearing with other water experts called together last week by the water authority to discuss the controversy over chloroform in the Occoquan, Adams offered this analogy:

"One part per billion is the equivalent of one drop of vermouth in 50 barrels of gin."

Some of the scientists reacted with forced smiles, possibly because they have been dealing with minute measurements of chloroform and other contaminants for a couple of years. But their were hearty guffaws from most of the audience, which included many members of the water authority board and other officials involved with Northern Virginia's water supplies.

Earlier, Adams warmed up the meeting, billed as a scientific presentation by water experts, with this self-introduction: I've got doctors sitting on both sides of me, but I'm just a country boy myself."

When he was misidentified as "Dr. Adams" by Fred C. Morin, chairman of the water authority board, he quickly pointed out he was a "mister," not a "doctor."

In his job at the state health department, Adams is responsible for monitoring the quality of the water that is treated at the Occoquan and piped to 600,000 customers in most of Fairfax County, Alexandria, Falls Church and part of Prince William County.

The member of the water authority board who was not amused by the tone of the evening was David Russell, who has sometimes been a minority of one since his appointment last fall by Fairfax Supervisor Audrey Moore (D-Annandale), herself often lone voice on environmental issues.

"Frankly I think the whole thing was staged," Russell said. "I was under the impression the experts were coming to address the board. I didn't know it was going to be treated as a the atrical event."

After Adams and other officials spoke, Russell asked several questions regarding the newly but rapidly developing data on chloroform in water. At one point, chairman Morin broke into Russell's questioning to remind him there was other business to discuss at the meeting.

Russell, like other members of the authority board, learned about the high levels of chloroform in the Occoquan's treated water from a story published last week in The Washington Post. The story was based on an unpublicized report, dated January, 1977, that was prepared by the Occoquan monitoring task force made up of teams from Virginia Polytechnic Institute and the Carborundum Co. of the Niagara Falls, N.Y., and presented to the EPA.

Although only Russell has been outspoken in his criticism of the authority's handling of the chloroform question, another board member has appeared less than pleased. Richard J. O' Brien said in an interview last week: "If the staff was aware of the potential health risks of the data. I think we (the board) should have been told. But I'm not certain they were."

Data on chloroform as a carcinogen and the presence of the chemical in various water systems around the country has been developing since 1974. The EPA gave notice of its intention of setting limits, together with optional thresholds, last July 14.

According to Dr. Robert C. Hoehn, a professor of civil engineering at VPI and one of leaders of the Occoquan monitoring project most of the organic material that reacts with chlorine to form chloroform comes from runoff, not from effluent discharged by the various sewage-treatment plants upstream from the reservoir.

Supervisor Moore and some other Fairfax officials think most of the runoff comes from Prince William side of Bull Run, the main tributary feeding into the reservoir. They point out that on the Fairfax side, the Occoquan is heavily buffered by parkland, while on the Prince William side, there is developed land running to the shoreline.

Runoff carries organic material not only from farms but suburban lawns, streets gutters and parking lots.

Water authority officials were told at the meeting meeting that several steps could be taken to reduce the amount of chloroform in the reservoir's treated water. One method experts said, would be filtering out more organic material before actual chlorine treatment begins. Another, they said, would be to disinfect the water at a later stagein the treatment process.