Montgomery County School Superintendent Harry Pitt, seeking to avoid a repetition of this year's bitter budget battle with the County Council, gave a council committee notice yesterday that the schools may need a $50 million increase next year just to maintain current services.

At the unusual conciliatory meeting, held well in advance of budget sessions, which usually begin in January, Pitt stressed that the $50 million was a still "soft" estimate and could be higher.

The projected 1988-89 budget increase is $9.5 million larger than this year's increase, which the council enacted after a series of emotional public hearings and debates.

The increase is needed, Pitt said, to pay for $30 million in salary increases already negotiated for teachers and service employes and to staff and equip seven schools scheduled to open in the upper county in the fall of 1988. Pitt said he has not factored in any increase for new programs.

The meeting was generally relaxed and low key, but it ended on a sour note when council member William Hanna cautioned school officials that the coming year "will be worse than last year."

Hanna indicated that the council may be in the position of having to finance the salary increases at the expense of any additional money for new programs.

Pitt's estimate includes the salary increases and $19 million in expenses associated with the opening of six new elementary schools and a new high school. It also includes increases connected with the expanding elementary school population, and increases for additional health benefits for employes, and an adjustment for inflation.

"I have to look that in the eye, and I don't see how you can do everything," Hanna said to Pitt, who was accompanied by top school staff members and school board members Marilyn Praisner and Sharon DiFonzo.

"I think we should have that as a sobering thought," Hanna said.

This year's school budget is $518.2 million, an increase of $40.5 million over last year's budget but $20 million less than the school board had requested. That cut from the board request, which caused the school board to eliminate 22 administrative positions and forestall plans to further reduce class size in elementary schools, was widely regarded the most divisive budget confrontation between the two agencies in at least a dozen years.

In an interview later, Hanna, who sits on the council's Education Committee with Isiah Leggett and Michael L. Subin, said he was worried about having to raise taxes again next year to finance the school budget. The council raised property taxes this year for the first time in five years. The increase of 7.4 cents per $100 of assessed value cost the average homeowner between $50 and $190 annually.

"I'm not attacking anybody," Hanna said. "I'm just trying to establish a philosophy of concern and responsibility on both sides."

Earlier, in describing the purpose of the meeting, Pitt said, "our goal is to be on the same wavelength. We don't expect to agree on everything, but we certainly will be using the same definitions." Later, Pitt said, "At this point I feel we're talking and the council is receptive and trying to understand our needs."

Subin, chairman of the Education Committee, said the $50 million figure is "within the ballpark" and "is roughly the figure I've been looking at."

He said a key issue during next year's budget discussions will be how much money the school system gets for new programs: "I don't see how we can go another year without including something for improvements."