Shirley Franklin took on the title of Atlanta's "sewer mayor."

Her successor, Kasim Reed, may wind up being known as its "pension mayor."

Reed has crisscrossed the city in campaign-like form in recent weeks, warning civic leaders that pension reform is a critical challenge. In one speech, Reed likened the problem to Franklin's effort to fix the sewers, a $4 billion project that is still going.

Without sweeping changes, Reed said the city will be able to do little aside from policing, fighting fires and picking up trash. It also has hurt the city's bond rating, which could force Atlanta to pay higher interest rates to borrow money to fund various projects.

"[Pensions are] putting the long-term health of our city in jeopardy," the mayor said in a recent speech to the Buckhead Coalition.

The city is projected to spend about $136 million on pensions in the 12-month period that ends June 30. That's nearly as much money as budgeted to the Police Department, about $154 million. .

"This is the city's biggest financial issue," said Tony Biello, a retired Atlanta police lieutenant who is chair of the city's police pension fund.

Reed has hinted at a few changes:

• Increasing the number of years new city workers can be vested from 10 to 15 years.

• Joining the Social Security system.

• Requiring new employees to contribute a portion of their salary toward their pension plan.

The mayor knows some changes could put him at odds with one key group of his supporters. Two of the city's three largest labor organizations endorsed Reed in the Dec. 1 mayoral runoff. City workers have not received a raise in two years. Some of those employees may have to make concessions in order for Reed's plan to work.

"I have to meet the challenges of the pension liability," Reed told the Atlanta Press Club. "It's going to be unpopular. It's going to put me on the opposite end of people I like a lot."

City pension leaders applaud Reed for tackling the issue, but they have concerns about some of what they've heard thus far.

Fire Rescue Lt. Kelen Evans, chair of the firefighters' pension fund, said he would "probably" fight changes to the vesting system. Biello says pension experts have told him joining Social Security would cost the city more money.

Evans fears joining Social Security would put too large a dent into the salaries of city firefighters.

"It would hurt the firefighters' pay," he said.

Former SunTrust bank economist Carter Doyle, who specializes in pensions, said the city joining Social Security would be a "wash" because it must invest in the plan. The good part, he said, is it would give city workers more sources of retirement income. Atlanta employees would have to vote in a referendum whether to join Social Security.

Reed has appointed a group led by former Atlanta Journal-Constitution publisher John Mellott to come up with pension recommendations. The mayor has said the recommendations could come within the next 30 days. Retirees won't be impacted by the changes, Reed has said. City workers hired after the changes will likely feel the brunt of them, Reed told some city workers during a pension board meeting nearly two weeks ago.

"My generation, in all candor, needs to take the hit on all of this," said Reed, 40.

For years, city union leaders say the three pension plans -- police, firefighters and general employees -- were underfunded. City officials increased benefits for their workers in 2001 and 2005, hoping, in part, to compensate for their low salaries. Employees get up to 80 percent of the average of their highest salaries when they retire, a larger pension than many places.

"Many employees look at Atlanta's plan as a crown jewel," Evans said.

The increases, however, were passed without specific ways to pay for them. At the time, Atlanta was in the midst of a construction boom, and the city coffers were healthy. Then came the recession. Revenues dropped, and the pension problem was exposed.

The city's three pension plans were funded between 55.9 percent and 66 percent, the AJC reported in September in its Atlanta Project series. Most financial experts say a pension plan should be at least 80 percent funded.

Many cities and counties are struggling with their pensions. In 2008, Philadelphia's pension plan was 52 percent funded, according to a study by the Pew Charitable Trusts. In Miami, city officials had to dip into their emergency fund last year to cover a $60 million budget gap, which they largely blamed on ballooning pension costs.

At the other end of the spectrum, the system that manages pensions for most municipal workers in North Carolina is 99.6 percent funded. Employees contribute 6 percent of their paychecks to the plan, and that makes up 29 percent of the fund's income.

State Senate leaders in Colorado last month adopted a pension relief plan that includes raising the retirement age for new employees from 55 to 60, increasing how much workers must contribute to their pensions and reducing cost-of-living adjustments for retirees.

Franklin offered some suggestions to Reed and the City Council in a report completed two weeks before she left office. They include a "hybrid" plan that allows future city employees to invest money into their own pension plans, which Franklin wrote could eventually save the city $10 million a year. She also recommended offering incentives to deter some longtime employees from retiring, which Franklin wrote could also save the city money.

Last year, Georgia lawmakers passed legislation that they hope will help local pension funds like Atlanta improve their performance. The changes might allow the city to invest in hedge contracts or derivatives that could be used to reduce risk, almost like an insurance policy. However, some analysts say such investments helped get insurance giant AIG in trouble. Reed, then a state senator, was a key sponsor of the changes.

Now, Reed must come up with more solutions, this time from City Hall.

Staff writer Russell Grantham contributed to this article.