In an emergency vote this week, the Montgomery County Council imposed limits on home building in the county for the next seven months while it reconsiders important elements of its planning policy.

The law will not immediately reduce the number of homes being built, planners and council members predicted, but will prevent a rush of panic building -- or hoarding of building permits -- by developers trying to avoid any future tightening of planning laws. Normally, about 10,000 building permits are issued for residential units each year.

More importantly, the move commits the county council to overhauling the 12-year-old Adequate Public Facilities Ordinance by the time most provisions of the emergency law expire in September.

Many on the planning board and council want it changed to ensure that schools, roads and other public facilties are ready when houses are built.

Linda Bell and Ron Wall, of the Committee for the Up-County, a homeowners' association in the area of the county where most home building is taking place, firmly supported the bill as a way of tackling the AFPO.

Pointing to severe rush-hour traffic problems in the area, Bell said, "the level of frustration of citizens in the upcounty has reached melt-down."

Several major builders in the county said they could "live with" the emergency law's restrictions, but complained they were not consulted ahead of time.

Council member David Scull, who introduced the legislation, said that was the idea: By springing it on builders unannounced, it prevented a last-minute rush for building permits.

The new restrictions fall far short of a moratorium, and do not apply if a builder meets any one of the following criteria:

* The preliminary plan was approved after Jan. 1, 1982.

* The preliminary plan contained a condition requiring the applicant to participate financially in a public-transportation improvement -- which includes most of developments approved after January 1982.

* The application has a contract of sale for the dwelling unit for which the permit is requested.

* The permits are for sale models.

* The permits are for moderately priced dwelling units in accordance with an agreement with the director of the Department of Housing and Community Development.

Furthermore, these restrictions do not apply to 25 single-family detached houses, 40 single-family attached units and three multi-familly buildings in each preliminary plan. This immediately exempts most of the smaller builders in the county.

Another provision -- which will not expire in September -- declares any building permit for new residential constuction invalid if work has not started within six months of approval.

The permit would also become invalid if the footings have not been built within six months of the time the permit is acutally issued to the builder, or if the second building inspection -- done after the foundation is finished -- is not completed 10 months after the permit is issued.

Because there are so many exceptions to the new limits, it is this final provision that could prove the most important. The planning board estimates there are around 20,000 residential units that have been authorized since January 1982, but not been built.

Stanley Halle, president of the Suburban Maryland Building Industry Association, said he shares the council's concern about the APFO -- epsecially where schools are concerned. But Halle said he believed the emergency limitations were unnecessary -- that builders learned their lesson in 1973, when they started hoarding building permits in fear of a sewer moratorium that never materialized.

Clarence Kettler of Kettler Bros., developers of Montgomery Village, agreed he could "live with" the restrictions, but said it would be a hardship. His company has $55 million in corporate debt, he said, and it is "the ability to keep building houses that keeps the company going."

Halle and Kettler agreed that the provision restricting the number of houses that could be built without a contract to sell would be a nuisance. Kettler said his company now has 307 houses under construction, of which only 103 have been sold. In this sort of situation, he said, it's important that the council sort out the AFPO quickly.

The AFPO issue has become especially pressing this budget season because of a dispute between the the school board and county executive Charles W. Gilchrist over two new high schools the school system says are needed in the fast-growing upper county -- and Gilchrist says are not.

This dispute has spilled over into another dispute between the council and Gilchrist over how public facilities are paid for -- and whether the county is raising enough money to pay for them. Several council members have said they fear the county is allowing residential development on the basis of planned public facilties that won't be built for lack of money.

The council was scheduled this week to begin meeting with the planning board to discuss what they should do with the APFO. Several council members are already talking of adopting county-wide a provision included in the Shady Grove West portion of the recently-approved Gaithersburg Vicinity Master Plan.

Under that provision, the council decided that subdivisions couldn't be started until the contract for roads have been actually executed. Under the current AFPO, those roads must be planned, but lack of funding means they remain unbuilt long after people have moved into new subdivisions.

"Once the contract for the road has been executed, the road is going to be built," said planning board chairman Norman Christeller. "The slippage occurs before that point." Christeller, who also wants this provision adopted under a revised AFPO, said it should also cover other facilities. "We've got to find a way to do the same sort of thing with schools," he said.