The Montgomery County Council yesterday raised the residential property tax rate for the first time in seven years. The 7.4-cent increase in the rate will boost the tax bills for most county property owners between $50 and $190.

The council voted unanimously to set the rate at $3.008 per $100 of assessed valuation, up from the current $2.934 per $100. The tax revenue will fund the $1.14 billion county budget for the fiscal year starting July 1. The budget provides for increased services to meet mushrooming county growth.

Robert K. Kendal, confirmed by the council yesterday as the new budget director, urged an increase of 6.8 cents. He said County Executive Sidney Kramer found that figure "more palatable" because it did not cross the "psychological threshold" of 7 cents.

The council went along with the recommendations of its staff director, Arthur W. Spengler, who said increasing the rate by 6.8 cents would cut too deeply into the county's unappropriated surplus. At his recommendation, the council agreed to maintain an unappropriated surplus of about $30 million.

The property taxes that Montgomery residents pay vary widely from area to area because of different recreation, sanitary and fire district levies as well as a staggered scheduled of property reassessments for different parts of the county.

The typical residential real estate tax bill, with the increased rate, will range between $1,100 and $1,700, according to information provided to the council.

In addition to the county's property tax, property owners pay a state levy of 21 cents per $100 of assessed valuation, over which the county government has no control.

The tone for the annual ritual of setting the tax rate was sounded by council member Bruce Adams, who said that "no one likes to increase taxes" but the council must do its best to be "prudent" and provide essential services. Montgomery's budget, the largest of any suburban jurisdiction in the area, reflects a growing need for services in a county hit by a development boom and with increasing cultural and racial diversity.

Council member Michael Gudis said the tax increase would have been twice as great if the council had given the county Board of Education all the money it wanted. The school board had sought $538.2 million to provide for pay increases to teachers and staff and to improve school programs. The council allocated the schools $518.2 million.

In looking to next year's tax prospects, Kendal noted that the school system entered into a three-year contract with its employes, which means the county will have pay for the raises and will be hard pressed to come up with money for program changes. Asked if he expected another tax increase next year, Kendal responded, "I hope not."

In other action, council member William E. Hanna Jr. introduced legislation intended to toughen county laws on smoking in public places. The county already bans smoking in elevators, public schools, health care facilities, county government buildings and large retail stores. Hanna's bill would extend the prohibition to most other public areas, including lobbies, waiting rooms and restrooms of businesses and theaters.

He said the bill "will further the county's efforts to improve the overall environmental health of the community." Hanna, who once opposed antismoking legislation, said the legislation is intended to round out the county's stance on smoking and represents "an evolution, not a revolution."

The bill, if approved, would exempt bowling alleys, beauty salons, and barbershops. Restaurants are governed by another law that requires those with more than 50 seats to provide smoking and no-smoking areas.