WESTPORT — The Board of Finance unanimously approved a flat mill rate for next fiscal year, amounting to no tax increases for most Westport residents.

“This would be the fifth year in a row our tax would be flat,” said finance board Chairman Brian Stern, with the rate set at 16.86 mills and a 10-percent reserve, per policy guideline.

But financiers cautioned it may be the last time this would happen for the foreseeable future.

“One of the things we’ve been struggling with this year is where the state is going to stand with the teacher retirement benefits,” said Gary Conrad, finance director for the town.

He said based on discussions with state legislators it was likely that Connecticut was soon going to require municipalities to carry part of the burden of this cost, proportionate to its teacher salaries.

“As we understand, the vote will go yes. ... That’s basically another $607,000 in expense,” he said, with that number increasing the following year and beyond.

“I’m very concerned about next year,” said BOF member Lee Caney, who indicated he would have almost preferred some increase, as next year it was likely there could be a significant one.

“I think people have to be aware next year,” he said

“Within two or three years it’s going to be up to four or five million ...” BOF member Sheri Gordon said. “Unless there’s some miracle, it’s really going to impact our tax rate.”

“We have to, in my judgment, look over our operational costs next year,” Stern said, noting there might be savings to be had.