Organizations using Montgomery County public school buildings would pay 8 per cent more beginning next summer, under a proposal now being studied by the Montgomery County board of education.

Raising the hourly charge from the present $2.50 to $2.70 an hour for weekday use after 5 p.m., and from $3.25 to $3.50 for weekends and holidays, will offset higher utility and salary costs, according to superintendent Charles M. Bernardo. School related groups, such as PTAs would not be affected since they are not charged for using school buildings.

"If approved, the new rates will take effect July 1," said Paul A. Henry, associate superintendent for business.

The proposal also increases the hourly rates for the hiring the extra personnel to $10.30 for a building service worker, $10.10 for cafeteria managers, $9.70 for instructional equipment aides, and $5.70 for cafeteria workers.

In addition, the mileage rate for field trips would increase to 31 per cents per mile and the hourly rate for bus drivers to $6.30.

The board has invited comments on the proposed changes. They should be sent to Dr. Charles Bernardo, Superintendent, at 850 Hungerford Dr., Rockville, Md. 20850, by Dec. 31.