Fairfax County, unable to cope with the surging pace of its residential development, is trying to channel some of the growth to equally affluent but slower-developing Montgomery County.

Fairfax officials led by Acting County Executive J. Hamilton Lambert last week took a surprising initiative in devising a tentative regional sewer solution that could hasten the pace of development in Montgomery County as well as in the District of Columbia.

Under the proposal, which must be approved by the federal Environmental Protecting Agency, Montgomery would get an extra 3.5 million gallons of treatment capacity at the Blue Plains regional plant -- enough to handle 35,000 new residents.

"we want to see some of our growth go to Montgomery," said Fairfax board chairman John F. Herrity (R), who in the past has been a strong proponent of growth. Fairfax Supervisor Alan H. Magazine (D-Mason) agreed: "Fairfax has taken the brunt of the region's growth for too long. We've tried to control it, but because of the state courts and the General Assembly, we find ourselves unable to assimilate the growth."

Herrity said his position is not an about-face. In the past, he said, he didn't support growth-control measures because they were legally unsupportable. Channeling development to Monrgomery "is a way of dealing with market forces realistically," he said.

The present rate of growth in Fairfax "is not in the public interest," Herrity said.

Too much of Fairfax's growth, according to top planning officials, has leapfrogged beyond settled areas. This suburban sprawl has created a need for expensive new public services such as roads, schools and fire protection in the Northern Virginia county.

Supervisor Audrey Moore (D-Annandale), who has repeatedly criticized her colleagues over the past seven years for failing to take stronger measures to control growth, said "anybody who's supporting channeling growth to Montgomery is doing it because this is an election year. If the board was serious, they would stiffen construction standards, environmental standards and zoning requirements."

She cited the board's recent consideration of widescale rezoning in the thinly populated Occoquan and Great Fally areas. The rezonzing to lower densities would have curbed tract-style development in those areas. But in the face of vociferous opposition by many landowners, the supervisors backed down.

Yesterday, the Environmental Quality Advisory Council, a citizen group that advises the board, told the supervisors that the environment is getting a low priority in county decisions on land use.

While Fairfax has a booming housing market, with 37 percent of all area building permits recorded in 1978, north of Fairfax in Maryland, Montgomery has a sluggish one.

According to Royce Hanson, chairman of the Maryland-National Capital Park and Planning Commission, Montgomery is able to absorb about 5,000 new houses and apartments annually, but it has been getting about 3,000 -- less than half those being built in Fairfax.

One of the major reasons for the big housing gap between the jurisdictions is the availability of sewer lines. Fairfax has enough sewer capacity to handle its needs until about 1990. But Montgomery is straining for capacity, and a proposed plant, even if approved by County Executive Charles W. Gilchrist wouldn't be ready until about 1985.

Montgomery officials, unlike their Fairfax counterparts, are confident they could have more growth without putting a severe strain on the county's ability to provide new services.

"We have more court sanctions than Virginia jurisdications," said John Hansman, assistant director of community and economic development. "If we find that public facilities -- especially transportation -- are inadequate we can turn down a subdivision."

Fairfax County's willingness to help Monrgomery County has its limits. Fairfax does not want to give up any commercial and industrial development, which generally more than pays its way unlike housing projects. But one high-ranking Fairfax planner acknowledged yesterday that if Montgomery gets more sewer capacity, it might attract some industrial growth that otherwise would go to Fairfax.

Though Fairfax lately has been garnering more business growth than Montgomery, the Maryland suburb still holds an edge overall. While commerce and industry account for only 14 percent of the tax base in Fairfax, they represent 27 percent of the tax base in Montgomery.

If Fairfax continues to be the area's hottest housing market, the newest regional forecasts see the Virginia county passing Montgomery in population as soon as next year.