A task force has recommended that Montgomery County purchase a building to house its police department instead of continuing to lease space at Rockville Mall.

The task force recommended that the country negotiate to purchase buildings at 2350 and 2401 Research Blvd in Gaithersburg, which were quoted at prices of $1.7 million and $2.17 million, respectively.

The task force also recommends that the police move into the new county buildings in 1987 instead of spring, 1980. when the first phase of the $125 million project is expected to be ready for occupany. One of the reasons the complex is to be built is to centralize county offices. The county now leases more outside space than it occupies in the current county office building.

At Tuesday's County Council meeting, Robert A. Passmore, assistnat county administrative officer and head of the task force, asked the Council for advance approval of the recommendations. The Council, however, voted to consider the request if it were made an amendment to county executive James P. Gleason's capital improvements program, as is necessary for such purchases.

The task force recommendations followed a more than six-month search for alternatives to the quarters which the police department is using at the mall. Accroding to a memorandum that the task force sent to Gleason, there have been problems at police quarters with ventilation air conditioning, water leaks, cockroach infestations and lighting since the space was leased in 1973.

The county is leasing a total of 52,405 square feet and the mall of $21,442.37 a month. Of that, 20.400 square feet is basement space used by the police department and the domestic relations office. The task force is only recommending moving the police department out, saying that offices on the upper levels have fewer problems. The domestic relations office plans to relocate on the upper level in space vacated by the Bicentennial Commission. The initial lease for the space expires July 24 and the county has until April 24 to notify the lessor if it intends to take the first of two possible option years.

The police now lease 10 per cent of the $14 million mall, which has been operating in the red because of high vacancy rate, its owners say.

On the seven-member task force were representatives from the police department, department of community and academic development, office of facilities management and services and office of the county attorney.