ROCKLAND, Maine — City officials have asked the regional school district to consider changing the cost-sharing formula to relieve the tax burden on Rockland.

The chairman of the school board said he is open to re-examining the cost-sharing formula.

Acting City Manager Tom Luttrell, Mayor Frank Isganitis and Councilor Louise MacLellan-Ruf met Monday with Regional School Unit Superintendent John McDonald, Business Manager Peter Orne and Board Finance Committee Chairman Donald Robishaw Jr. to discuss the proposal. The council had authorized the meeting at its Jan. 12 session.

Luttrell said nothing was accomplished, but the city delegation asked for the formula to be evaluated with the departure of St. George from the district as of July 1.

Voters approved the formation of RSU 13 in November 2008 and the merger became effective on July 1, 2009. The merger agreement resulted in an assessment formula based on the number of students from each of the six communities and the property values of each community. With the emphasis placed more on enrollment, the formula has resulted in Rockland paying a larger share of the costs each year.

Luttrell said the council is relying on the school district to come up with a proposed formula change, saying it was not Rockland’s responsibility.

Rockland is paying $8.1 million to the school district this year, slightly more than a third of the entire local share. St. George is second largest contributor, at more than $4.4 million. The estimated cost to RSU 13 to run the St. George school has been about $2 million.

Luttrell said he had heard from some school board members that Rockland would see a 20 percent increase in its school payments with St. George’s withdrawal. At Wednesday night’s RSU 13 finance committee meeting, however, the superintendent and business manager said that it was too early to know what impact St. George’s withdrawal will have on the overall school budget.

McDonald told the finance committee that it should anticipate about 75 percent of the St. George high school-age students will decide to stay at Oceanside High Schools in Rockland and Thomason, but said he has received no numbers from St. George yet.

St. George Superintendent George Joseph said Friday he does not have numbers yet on where the high school students will be going. Besides the high schools in Rockland and Thomaston, both Camden Hills Regional High School in Rockport and Medomak Valley High School in Waldoboro will accept St. George students.

There are about 100 students from St. George in grades eight through 12.

Board Chairman Steve Roberts of Rockland said Friday that he was open to looking at changing the formula.

“The formula ought to be re-evaluated with St. George stepping out of the district,” Roberts said.

He said that he has heard rumblings from Rockland about the need for a change since he got on the board.

When St. George leaves the district, the remaining communities will be Rockland, Thomaston, Owls Head, South Thomaston and Cushing.