BRUNSWICK, Maine — Since the 1990s, Brunswick High School graduation ceremonies have been staged at Bowdoin College, in an event that has become, for some, a beloved community celebration.

It has also become possibly the most expensive graduation in Cumberland County.

Now, as the the estimated cost of next year’s commencement nears $28,000, School Board members are reconsidering the venue — and hearing from students, families and staff opposed to any change.

Brunswick for years held commencement at Bowdoin’s Farley Field House, and more recently at the new Watson Arena.

The arena has many advantages: lots of parking, it’s weatherproof, and has a superb audio-visual system. And it is big enough to hold more than 3,000 people, which opens the ceremony to extended families and friends who may not otherwise be able to attend.

But using such a venue comes at a large cost. According to Superintendent of Schools Paul Perzanoski, this year’s graduation was expected to cost almost $15,900.

Typically, Brunswick is able to piggy-back on Bowdoin’s alumni weekend, which is held around the same time as graduation, allowing the school department to get some “efficiency savings” from vendors who provide chairs, sound and audio-visual systems, college spokesman Doug Cook said.

In other words, the school department has shared its costs with Bowdoin.

Those three items together usually account for a little more than two-thirds of the school’s overall budget, according to figures provided by the school department: almost $1,700 for chairs, more than $5,600 for the sound system, and almost $4,500 for audio-visual equipment.

The remaining funds are spent on sign language interpreters, $500; police, $900; and department employees, $1,500. Renting Watson Arena costs the department about $1,200.

Next year, however, the school department is bracing for almost $11,800 in unexpected costs because of a 4-3 vote by the School Board in April to push back graduation by about a week.

Bowdoin’s events director, Tony Sprague, hinted at the increased cost in an email to school department staff in June.

While pushing the date back would not affect the cost of renting the facility, it may “affect some of the areas like the chair rental and other vendors as this would require leaving their equipment on site for an extra week,” Sprague said.

Because of the delay, the school department will be charged the full amount for chairs, audio-visual, and sound equipment, pushing the overall cost of graduation to an estimated $27,666, according to projections provided by school officials.

The realization that the school department could be spending that much on graduation was sobering, School Board Member Rich Ellis said.

“For me, its not the venue, it’s the cost,” he said, noting the price of audio-visual equipment in particular seemed uncommonly expensive.

Even without the added costs, Brunswick has one of, if not the, most expensive graduation in the region, Perzanoski said.

According to a survey compiled by the school department, South Portland and Cape Elizabeth both budget $3,000 for their ceremonies: Cape Elizabeth at Fort Williams Park, and South Portland at the high school.

Yarmouth, with a budget of $6,550, and School Administrative District 75 (Mt. Ararat High School in Topsham), budgeting $8,500 to $10,500, both conduct commencements at their schools.

Only Bonny Eagle High School in Buxton comes close to Brunswick’s cost, budgeting $12,000 for its ceremony at the Cumberland County Civic Center in Portland.

“We shouldn’t be spending twice as much to graduate our kids as every other school district,” Ellis said, “particularly when we have priorities that are going unfunded.”

Board member Corrine Perreault, who encouraged moving the graduation date back, said she didn’t realize it would mean a huge cost increase.

Unfortunately, there doesn’t seem to be an easy, or cheap, solution.

In a memo with some preliminary research and talking points circulated to board members, Perzanoski pointed out that Brunswick High School has about half the capacity of Watson Arena.

Holding graduation at Brunswick High would add further complications, like instituting a ticketing system for guests, and working out rain arrangements, the memo said, and even then, graduation could wind up costing just as much as the current venue.

Even though the School Board has yet to fully discuss the issue, it has already sparked controversy.

Rumors about moving the ceremony to the high school have led to a flurry of letters from students, families and staff, the vast majority in opposition to the idea.

For many, the ceremony has transcended from being just a graduation to an annual celebration of Brunswick’s community.

“I hope you truly consider how changing the site would impact so many people,” one parent wrote. “I believe it is worth the cost to hold the graduation at Bowdoin and I do not feel any monetary savings would be significant enough to constitute a change of venue.”

A high school student in the class of 2015 added her voice to the calls to stay at Bowdoin.

“Since I was a little kid I can remember thinking about graduation, it is a proud tradition in Brunswick,” she wrote. “It only makes sense to have graduation at Watson Arena and it would be very disappointing for the class of 2015 if we were forced to have it at Brunswick High School.”

Board members intend to discuss the issue in August, according to Chairwoman Michele Joyce.

The school department has already booked Watson Arena and it is unlikely the board will move to an earlier date, not least because of a state law requiring that students graduate up to five days before the end of the regular school year.

Regardless, with the attention the issue has been getting, the board may have to act.

“I think we should have an answer for the upcoming class,” Joyce said. “It’s an emotional issue.”