Seattle labor activists scored a major win last year when the city became the second in the country to pass a $15 minimum wage law. But working conditions for many local service workers remain poor, in part due to lax enforcement, according to a new survey by a group representing Seattle restaurant employees.

Restaurant Opportunities Center (ROC) Seattle — part of ROC United, a national labor group that campaigns on minimum wage issues — found in its survey of 524 Seattle-area restaurant employees that low wages and illegal labor practices persist in the industry, despite the minimum wage law and other legislation meant to improve conditions for low-wage workers.

The survey found that 42.7 percent of respondents earned “poverty wages,” or wages below a threshold the group set at $12.25 per hour. Seattle’s $11 an hour minimum wage will gradually increase to $15 for all employers by 2021.

“Many restaurant jobs in the Seattle area are low-road jobs characterized by few benefits, low wages, and poor workplace conditions,” ROC Seattle said in a statement issued Tuesday. "Our report also unearths a range of serious problems related to the availability of benefits, hiring and promotion practices, workplace discrimination, and job-specific training opportunities."

Wage theft was also widespread, the survey report said. More than one-fifth of respondents said they had worked off the clock without pay in the past year. And 38.8 percent of those who had worked more than 40 hours per week at some point during the year said they had not received the time-and-a-half overtime compensation required by federal law.

The report praises Seattle's $15 minimum wage law, paid sick leave bill and similar legislation, but concludes that “enforcement has been largely lacking, effectively diminishing the reach of these gains.” The group recommends higher penalties for employers found guilty of wage theft, and public outreach to make sure workers are informed of their legal rights.

Activists have been campaigning for stronger labor law enforcement since the Seattle minimum wage proposal became law. In October 2014 the National Employment Law Project issued a report recommending that city agencies form partnerships with community groups to monitor labor practices at neighborhood businesses.

That strategy has been adopted with some success in San Francisco, which authorized a $15 minimum wage law in November 2014. Since then, San Francisco activists have been pressing for more aggressive enforcement and more resources for the city's Office of Labor Standards Enforcement.

The Seattle city government has adopted elements of the San Francisco model, forming its own Office of Labor Standards and distributing $1 million in grants to community groups such as the Seattle NAACP and the Chinese Information and Service Center to help with enforcement efforts.

Wage theft is common among low-wage employers in the United States. A 2008 survey of low-wage workers in Chicago, Los Angeles, and New York City found that 76 percent of those who worked overtime “were not paid the legally required overtime rate.”