SOUTH PORTLAND — Schools would have to eliminate 21 full-time positions next year to operate under a budget that avoids a tax increase, according to possible spending scenarios presented to the Board of Education on Monday.

In addition to the $42.4 million version that would not increase property taxes for schools in 2011-12, Superintendent Suzanne Godin submitted a second proposal that would require a 2.5 percent tax increase and a third that takes a “needs-based” approach, disregarding the impact on taxes.

The version with no increase was requested by the City Council, which must vote on the school budget before it goes to residents for a citywide vote.

“We had a significant chore to bring in a zero percent budget. That was not done lightly,” Godin said.

Total spending would increase 3.2 percent from the current budget of $41.1 million. The amount needed from taxes would remain at $33.7 million. The property tax rate for schools is projected to remain at $10.05 per $1,000 assessed valuation.

The proposal would cut 2.5 teaching jobs: a half-time social studies teacher at the high school, where enrollment is declining; an English Language Arts teacher in the program for academically gifted students; and the preschool teacher for a program that began in recent weeks.

Other cuts include six education technicians, one guidance counselor/social worker, two tutors, two middle school library clerks, a high school attendance clerk and seven custodial positions, six of which are vacant.

Nine of the positions are funded now with one-time federal stimulus funds.

The budget without a tax increase would also eliminate stipends for some activities, impose fees for sports and other activities, and turn four custodial positions into part-time jobs.

School officials expect less state funding than South Portland got a couple of years ago.

The projection for the coming fiscal year is $2.1 million — more than the $1.8 million in the current budget but less than the $3.4 million to $4.8 million that South Portland got in previous years.

Godin’s proposed budget would use $1.2 million in surplus, leaving the district with $1.6 million in surplus. One-time funding of $1.2 million from the federal jobs bill would pay for 29 positions for a year.

Under the budget with a 2.5 percent tax increase, 12 of the positions would be spared: the English Language Arts and preschool teachers, five ed techs, the guidance counselor/social worker and the three clerks.

Activity fees are not part of that budget.

The “needs-based” budget would fully fund a curriculum director for science, technology, engineering and math and the preschool teacher, which relied on grant funding in other versions.

Also included are a middle school resource officer, six ed techs, money for elementary and middle school field trips and increased funding for professional development and building maintenance.

The increase the “needs-based” budget would cause in the tax rate was not available Monday night.

The spending totals were not available for the budget with a 2.5 percent increase or the “needs-based” budget.

Staff Writer Ann S. Kim can be contacted at 791-6383 or at: akim@pressherald.com