Workers in many urban areas have recently tangled with unsupportive business leaders and politicians to enact paid sick leave ordinances (PSLOs). Just last week in New York, a paid sick leave bill passed after three years of back-and-forth between city officials and workers’ advocates, though Mayor Bloomberg has vowed to veto it.

Meanwhile, San Francisco’s paid sick leave policy is in its sixth year. Voters approved San Francisco’s PSLO in November 2006, making it the nation’s first law allowing all workers, including part-time workers, to earn and use paid sick days. Washington, D.C., Portland, Seattle, Philadelphia, and now New York have since joined San Francisco as the only cities in the nation with paid sick leave ordinances. Connecticut, meanwhile, has a statewide paid sick leave policy, the only one of its kind in the nation.

San Francisco’s PSLO allows workers to earn paid sick days after three months on the job, to earn up to a maximum of five days per year in small firms and nine days per year in larger firms, and to use those days for their own health needs as well as those of other family members (including a “designated person”).

Though the details of various PSLOs vary, San Francisco’s policy can help us understand the effect paid sick leave has on employees and employers. According to a 2011 study by the Institute for Women’s Policy Research (IWPR), which is based on a survey of nearly 1,200 employees and more than 700 employers in San Francisco, the city’s paid sick days policy has benefited employees without reducing employer profitability. The report found that under the policy, 59,000 San Francisco workers who had not previously had paid sick days started receiving that benefit. That’s 17 percent of the city’s workforce.

More than half of the San Francisco employees who now have paid sick days reported that they’d experienced some benefit because of the law’s passage: they were better able to care for their own health or the health of a family member, their employer increased their number of sick days because of the ordinance, or their employer became more supportive of employees using sick days.

The IWPR report found that single mothers and workers with chronic health conditions are most likely to report needing paid sick days. Women workers, as a broad group, were found to be somewhat more likely than the average worker to need paid sick days.

Jennifer Piallat is the owner of Zazie, a popular San Francisco restaurant. Since Piallat purchased the restaurant eight years ago, she’s worked to establish good working conditions for her employees. But when she first heard about a proposed city paid sick leave ordinance (PSLO) in 2006, she balked.

“I thought the sick day ordinance could become an excuse for my servers or other employees to call in sick at the last minute and leave shifts unstaffed,” Piallat said. “Turns out, that hasn’t been a problem at all.”

Nor has the ordinance cost her nearly as much money as she originally expected. Piallat anticipated paid sick leave for her 32 employees would cost $35,000 per year, but since 2006 she hasn’t spent more than $7,000 per year total on her employees’ sick leave.

Several of Piallat’s employees have needed sick days for serious health concerns; one of her servers recently suffered appendicitis and another a kidney infection. One Zazie server, Diana (who asked that I not reveal her last name), used sick leave when she caught the flu. “Knowing that I had access to sick pay gave me some peace of mind and allowed me to focus on healing rather than the financial loss and the added pressure missing work brings,” she told Rewire. “I have worked for employers without sick pay in both San Francisco and New York City, and that made me reluctant to call in sick.”

BiRite Market is another San Francisco business that has been enthusiastic about the city’s paid sick leave policy, not just because it’s good for its workers, but also because of how the policy reflects on the business as a whole. “We are super proud to have this initiative in our city,” Paula Brannon, human resources director at BiRite, told Rewire. “We firmly believe taking good care of our employees reflects well on our guests, and we want to make sure we have a healthy work environment.”

Though several attempts by Rewire to find a San Francisco business owner who would go on record opposing the law failed, many business owners spoke out against the bill before and soon after it was passed, citing concerns about rising costs and employees who might abuse the benefit.

However, most employee complaints arising from the city’s PLSO have been resolved with ease. Between February 2007 and December 2012, the San Francisco Office of Labor Standards Enforcement received 305 complaints—an average of about 4.4 complaints per month—from workers about employers’ failure to comply with the ordinance. Most cases were resolved fairly easily, and no paid sick leave ruling has ever been appealed. Over 100 of the complaints resulted in back wages and penalties totaling about $194,000.

Piallat’s experience shows that complying with a paid sick day ordinance may not cost as much as employers think it will. In fact, paid sick days should be considered an investment. The IWPR report points out that when employees work while they’re sick, they are less productive and more likely to infect colleagues and customers, which can yield much higher employer costs down the road.

Opposition to paid sick leave will likely persist in some U.S. cities, while the national movement for paid sick leave works to emphasize the public health benefit of paid sick time. Piallat, who was a server for many years before becoming a restaurateur, understands the public health concern all too well. “One sick server could get 120 people sick,” she said. “They’re touching glasses, silverware. Having people work in a kitchen or wait on you when they’re ill does not make sense.”