Santa Rosa and its firefighters have reached a tentative, nearly three-year labor agreement calling for them to receive salary increases totaling 4.5 percent but also requiring them to pay 12 percent toward their pensions by 2015.

If approved by both sides, the deal is expected to save the city nearly $1.7 million over the life of the contract and eliminate the city's long-standing but politically problematic practice of paying firefighters' pension contributions for them.

"We think we've achieved the city's goal and did it in a way that was palatable and explainable to our members," said Tim Aboudara, president of the Santa Rosa Firefighters, Local 1401.

The deal has yet to be ratified by the firefighters, who are expected to vote on it Oct. 10. It would then head to the City Council on Oct. 15.

But the public got a sneak peek at the impact of the changes Tuesday when the city's actuary outlined how the new agreement would affect different employees and city coffers.

John Bartel explained that the bulk of the savings to the city will come from the elimination of the practice of the city paying something called "employer paid member contributions" for firefighters hired before 2012.

The practice already had been eliminated for newer workers, including those hired under a second tier of lower benefits established by the city and a third tier of even lower benefits established by the Public Employees' Pension Reform Act of 2013.

But the vast majority of the existing firefighters, 108 of 122, still are receiving the benefit, which amounts to 9 percent of salary. A pension task force formed in 2011 recommended eliminating such contributions from city labor contracts.

The changes would go away as soon as the new contract takes effect. Most firefighters will see their pension contributions go from 5 percent today to 9 percent for the remainder of this year. Then it would tick up to 10.5 percent in 2014 and top out at 12 percent in 2015. The six employees in the second tier and the eight hired under the third tier already pay 9 percent and 10.5 of salary, respectively, toward their pensions. They will also see their pension contributions rise to 12 percent by 2015.

In recognition of the increases, firefighters will receive salary bumps of 2 percent in 2014 and 2.5percent in 2015.

Other changes in the contract involve how paramedics are paid. Currently, firefighters working as paramedics get a 10 percent salary bump that stays with them as they rise up the ranks, according to Fran Elm, the city's human resources director.

But the new contract strips that premium pay from the higher ranks such as captains and restricts it to firefighters, Elm said.

Most of the city's 1,200 employees except bus drivers, who just inked a new deal, have been working without a contract since July 1. After years of furloughs, higher health care costs and no raises, many are holding out for salary increases, Elm said.

"So this year, it's been difficult negotiating with them," Elm said.

The negotiations with the largest bargaining unit, Santa Rosa City Employees Association, reached an impasse and the two sides are in mediation. The city attorneys already declared an impasse and went through a mediation process that didn't resolve the dispute, Elm said.

"We're just grateful that ... we were able to reach a deal we both think we can get passed without having to go through one of these protracted and expensive processes," Aboudara said.

You can reach Staff Writer Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com. On Twitter @citybeater.