For nine years, Reyna Mendez made above minimum wage cleaning the public parking garage on Elm Street in downtown Bethesda. Her pay was guaranteed by a Montgomery County law requiring a “living wage,” meaning enough to survive in this expensive region.

But in 2012, new deductions appeared on Mendez’s pay stub for benefits she neither asked for nor, in some cases, received — including cellphones, uniforms and vision coverage. Her pay shrank from $13.65 an hour to about $8.65.

Mendez says she was fired after she confronted her bosses at the Gaithersburg-based Camco. Now, she and seven other garage cleaners, all Hispanic women, are suing the company and the county for back wages and damages.

Their situation exposes a weak spot in the affluent county’s aggressively liberal lawmaking regimen. Despite a raft of statutes intended to protect vulnerable workers, oversight and enforcement remain spotty. Experts say there are other jurisdictions that do a better job of making protections stick.

A 2013 county audit confirmed some of the women’s allegations, including Camco’s practice of improperly deducting the entire cost of health-care premiums from their paychecks. In Mendez’s case, that amounted to more than $500 a month. The county terminated a prior contract with ­Camco in 2010 because it kept virtually no payroll records, also a violation of living-wage regulations.

County attorneys maintain that Montgomery has no legal obligation to the women because they worked for an independent contractor, not the government.

“It’s the ultimate hypocrisy,” said John Riely, the women’s attorney. “These women do the kind of work that very few people want to do.”

Neither Camco executives nor their attorney responded to multiple phone and e-mail messages this past week. In a court filing answering allegations in the lawsuit, company owner Julio Arce denied “any and all liability.”

County government spokesman Ohene Gyapong declined to discuss the lawsuit because it remains pending. “The county recognizes and values the people who work to support our services and our residents,” Gyapong said in a statement. “The county is working to ensure everyone involved receives the compensation they are due.”

A motion by the county asking to be dismissed from the case was denied in Montgomery County Circuit Court. A hearing is scheduled for June 1 on a new motion, in which the county is seeking to be tried separately from Camco.

Montgomery’s living wage, $14.15 an hour, has been in effect since 2003 and covers about 400 companies that provide services to the county. The ordinance is most significant for employees of approximately 40 firms that do low-paying janitorial, cleaning and landscaping work.

About 140 cities and counties — including Arlington and the District — have similar statutes. Many were passed in the late 1990s and early 2000s, when efforts to raise the minimum wage for all workers were going nowhere.

As with many of the progressive laws Montgomery County legislators have passed in an effort to protect public health and welfare — including a ban on trans fats, a nickel tax on plastic shopping bags and a prohibition against asking questions about an applicant’s criminal convictions on job applications — Montgomery’s enforcement of its living-wage law is “complaint-based.”

That means there are no inspectors or compliance officers proactively checking for problems. For a company to be investigated, a worker would have to come forward.

Montgomery has one general services department staffer who is supposed to dedicate 30 percent of his time to checking into living-wage complaints. There is no daily fine for noncompliance and no requirement for firms to submit payroll information to the county certifying that proper wages are being paid. Nor is there any provision for disqualifying a firm that breaks the law from bidding on new contracts in the future, once a two-year penalty period has expired.

In fact, Camco — which was fired by the county in 2010 for not documenting what it was paying its workers — bid on and won the three-year garage-cleaning contract in 2012. The agreement, worth about $430,000, expires this month, and Camco is a bidder for the contract that will replace it.

Since 2003, when the law took effect, county officials say they have received 12 complaints that the law was not being followed. Eight led to findings of wrongdoing.

Stephanie Luce, City University of New York professor of labor studies, has analyzed living-wage laws across the country and said other jurisdictions are more aggressive in their enforcement.

She cited San Diego, which employs a living-wage manager and two senior compliance officers. Since 2006, when its law went into effect, the city has completed 57 investigations, found wrongdoing in 33 and recovered more than $385,000 in back pay.

Montgomery General Services Director David Dise, whose department oversaw county procurement until a recent reorganization, said the low volume of complaints received by the county “would indicate that the vast majority of companies comply with the law.”

But advocates say the low-skilled, mostly immigrant workers who depend most on the living wage are among the least likely to complain, out of concern for their job security or immigration status.

Grace Denno, who heads business relations and compliance for the county’s newly formed procurement office — taking over for Dise — said she thinks the lack of enforcement is the issue.

Denno also oversees compliance of the county’s separate ­“prevailing wage” law, which requires that construction workers on county-funded projects be paid the same as private-sector employees doing comparable work in the region.

The county employs an auditing firm full time to make spot checks at construction sites and ensure that workers are being properly paid.

Unlike the living-wage measure, there are monetary penalties — $10 per worker per day — for contractors who wait more than two weeks to submit proper payrolls to the county.

Denno said the number of violations found by the auditors “is much higher than if we just wait here for complaints.”

The garage-cleaning jobs are arduous, advocates say, with the women arriving at 6 a.m. to sweep, hose, scrub and polish in advance of the day’s traffic. ­Mendez, 41, said she sent most of her money to five of her children in her native Guatemala.

She feels betrayed by Camco. “After all these years, they tell me I’m fired,” she said through a translator.

Mendez and the other plaintiffs — six of whom are listed as Jane Does in court documents because they still work for Camco and fear retaliation — said they are also disappointed with county officials, who they said regularly inspected the garage and came to know the women well. While contractors came and went, they said, the county was the constant in their work lives.

Gilma Alarcon, who broke her arm falling down the stairway of a Silver Spring garage, said workers told the county numerous times about the improper deductions.

“They said they were going to help us,” Alarcon said.