That's equal to spending more than $8,000 per city resident - and could build the Golden Gate Bridge five times over in today's dollars. And yet, it's not enough.

Mayor Gavin Newsom and the Board of Supervisors are engaged in a heated battle over the coming year's budget and whether to make big cuts to public safety or social services, which both sides describe as a life-or-death decision.

They agree on one thing: asking voters to support a $368 million bond measure in November to repair streets, one of the most basic roles of city government.

And the problem isn't just created by the economic recession. Every year for the past 10 years, the city has had a budget deficit - despite a robust tax base including very strong property values. The city has asked voters to approve tax increases in eight of those years, according to the controller's office.

How is this possible with $6.6 billion at hand? City Hall officials and observers point to many reasons for the seemingly upside-down scenario. San Francisco is unique in California for being a city and county responsible for dual functions: the public works and public safety a city provides and the health and human services a county provides.

In part, the budget is so massive because it includes an international airport, a port and the Hetch Hetchy water system, all of which serve people far outside the city's borders - and all of which are paid for by the people who use them, not by taxpayer money.

About half the city's budget is taxpayer-funded, but much of that general fund is earmarked for specific purposes by voter-mandated set-asides for libraries, Muni, children's services, the Symphony, minimum staffing of police officers and more.

The controller's office released a report in March comparing San Francisco's spending with the spending levels in 10 cities and counties in California, including San Jose, Los Angeles, Sacramento and Alameda County.

The need to share the pain

It found that salaries and wages account for 54 percent of the growth in the budget over the past 10 years and now total $3.5 billion - or roughly $125,000 per city employee including benefits. The number of city employees - about 28,000 - hasn't changed much in that time.

Even laid-off city employees get some comparatively generous perks, including medical benefits for five years and remaining on a call-back list for five years.

Steve Falk, CEO of the San Francisco Chamber of Commerce, said that those working in the private sector earn an average pay of $75,960 including benefits. Falk said that, traditionally, public-sector jobs have come with better benefits packages because wages were so much lower.

"But over the years, they have not only caught up but surpassed the private sector and the benefits are still there," he said.

It's not just the business sector that sees this as a problem. Aaron Peskin, former president of the Board of Supervisors and an ally of labor, said that "whether they're cops or attorneys or on down the line," city employees are paid very generously and are driving the city's skyrocketing expenses.

"That's fine when times are fine and you can still afford to pave the streets and offer services and programs," he said. "When times are tough, everybody's got to share the pain. The No. 1 cost-driver needs to be adjusted."

Peskin said overseeing union contracts as a supervisor is a challenge because they're exclusively negotiated by the mayor's office and the board must vote yes or no to the entire package.

In 2007, Newsom gave police officers and firefighters a 23 percent pay raise over four years, which some critics say was an ill-timed ploy to get their support for his mayoral re-election that year and perhaps for his current run for governor. His proposed budget would grow both departments by several million dollars.

The controller's report found that San Francisco spends $458 per resident on the Police Department compared with $325 in other California cities and $239 per resident on the Fire Department compared with $111 elsewhere.

San Francisco 'values' costly

Health and social services, too, have seen tremendous growth over the past decade. The city's general fund contribution to the Department of Public Health has grown 28 percent to $1.3 billion and to the Human Services Agency by 16 percent to $619 million.

San Francisco spends more than twice the amount per capita on public health services other counties do, according to the controller's report. It spends $86.66 per capita on substance abuse services, compared with $15.13 in Los Angeles, $20.42 in Sacramento and $22.90 in San Mateo. It spends $300.63 per capita on mental health services, compared with $133.75 in Los Angeles, $117.57 in Sacramento and $124.59 in San Mateo.

"We need a great deal of services, and those are the values of San Francisco - humanistic and supportive of people who are very vulnerable," said Supervisor John Avalos. "It's part of our values, but now we have to figure out how to pay for it - that's the hard part."

Newsom said the notion that the safety net for the poor will be ruined by his cuts to social services is ridiculous.

"We're still doing an extraordinary amount even with these constraints," he said. "I know some of these cuts are tough but at the end of the day, we'll still be providing a diverse, extraordinary, culturally competent array of services that's become the envy of the nation."

Budget woes require reform

So how to make a $6.6 billion budget work? Gabe Metcalf, executive director of the San Francisco Planning and Urban Research Association, said the discussion needs to get beyond either cutting services or raising taxes.

"There's a third, best option: reform government to make it more efficient," he said. "They should take a look at work rules, contracting reform and civil service - new ways to increase productivity."

Many city officials are behind the idea of a two-year budget process in which a new budget is signed only every other year, allowing for more planning time in between.

The controller's report suggested other reforms, too, including building up the city's reserve fund for emergencies and identifying revenue increases to fund union raises.

E-mail the writers at hknight@sfchronicle.com and mlagos@sfchronicle.com.