The Montgomery County planning board has recommended approval of a subdivision in Wheaton that will be phased in to coincide with additions planned for a local high school, as part of an ongoing effort to balance development against overcrowded schools.

"The developers are going along with the phasing plan because they realize that, with the constraint of schools, the county may have had to deny the development altogether," said Joan N. Yamamoto of the planning staff.

Yamamoto said that many developments have been phased in, or built a section at a time, in the county, but that this is the first time the phasing has been timed to coincide with school expansion.

She said the board also included an unusual provision in the approval under which the developer will be able to drop the phasing plan without going through a formal process if school enrollment in the area drops below current expectations.

The developer, Peter J. Koutsos, has applied for a zone change to build a 93-unit subdivision of town houses and single-family homes on a 9.9-acre site on University Boulevard near the site of the future Wheaton Metro station.

Teen-agers living in the new development would attend Kennedy High School, which already is over its capacity of 1,624 students. But the county plans to add eight portable classrooms to the school in 1987, according to a recent staff report.

Yamamoto said the multifamily subdivision adheres to the county's master plan, which calls for dense residential development near Metro stations.

But in the last six months, the county has had to temper its burgeoning residential development because many schools are filled to capacity.

Money for school construction also is tighter than it has ever been because the state is contributing less.

Earlier this year, the county council asked the planning board to deny new residential development near overcrowded schools under the Adequate Public Facilities Ordinance, which allows the county to turn down development if there are not enough public facilities such as sewers, roads or schools to serve new residents.

Planning board members have voiced reluctance to deny development based solely on school capacity, however, because they say schools are flexible when it comes to accommodating students.

Board Chairman Norman L. Christeller said this flexibility would make it difficult for the county to win in court should a developer decide to sue.

For the past few months, the planning and school boards have been working out a policy regarding new development and school capacity that Christeller said would make the county's position stronger and more equitable.

The board already has shelved one proposed subdivision near overcrowded schools, and the developers of several more projects have voluntarily agreed to an indefinite delay while the policy is being worked out.

In the meantime, the planning board is looking toward alternatives such as the phasing project rather than denying new development altogether, according to Yamamoto.

She said studies by the school board staff showed that the proposed development in Wheaton would bring 37 more students into the local school system by the time it is completed.

The school staff reported that the local elementary and junior high schools are below capacity, but that Kennedy High School is overcrowded and unable to accommodate new students, Yamamoto said.

But she said the new development is needed in the Wheaton area because it includes 12 moderately priced units.

The county council, which has final say on all zoning matters, will vote on the application sometime this summer, Yamamoto said.