Philadelphia is dramatically expanding labor protections for domestic workers such as house-cleaners and nannies, including requiring those who employ the workers to have a written agreement outlining employment terms, pay rates, schedules, and benefits.

As part of a national push to improve conditions for these workers, City Council on Thursday unanimously passed what’s been dubbed “the domestic worker bill of rights,” legislation that also guarantees in-home workers accrue paid leave and sick days even if they work for multiple employers. The mayor is expected to sign the bill, which will take effect in May.

The adoption of what advocates say is one of the strongest bills protecting domestic workers in the nation is the latest example of Philadelphia ramping up labor protections for low-wage workers. The measure will apply to an estimated 16,000 workers in Philadelphia, the majority of whom are women of color, who don’t have the right to unionize under federal law.

“You are not alone. We are with you,” prime sponsor Councilwoman Maria Quiñones-Sánchez said to the workers gathered in the room, “and I appreciate the process in which we have undertaken this.”

The average annual income for domestic workers in the Philadelphia metropolitan area in 2016 was $10,000, according to an analysis by Pilar Goñalons-Pons, a professor at the University of Pennsylvania. Many of the workers are undocumented immigrants, and they work in intimate workplaces that, due to the isolation, are vulnerable to abuse.

Protections outlined in the legislation are extensive. While the bill could not set overtime pay or minimum wage due to state law that preempts the city from doing so, it requires employers to follow a written contract if the employee works more than five hours per month. If the employer doesn’t provide a contract, it will be presumed the staff is operating under a template agreement written by the city.

“Everyone in Philly will have a contract,” said Nicole Kligerman, director of the Pennsylvania Domestic Workers Alliance, “whether they know it or not.”

The legislation outlines what benefits must be offered at minimum, including periodic rest and meal breaks, and paid time off based on time worked. Workers’ hours will follow them, not the employer, through a novel “portable benefits system." (There’s an app for that.) Employers must also provide two weeks’ notice before terminating an employment contract (four weeks if the worker is live-in), except in cases of “significant misconduct.”

If city officials find an employer is out of compliance, the employer could face a fine of up to $2,000 per violation. Taking retaliatory action against a worker for filing a claim could yield further violations.

The Mayor’s Office of Labor will be responsible for enforcing the new protections and will rely largely on workers filing complaints. That means educating workers on their rights and employers on their responsibilities will be key. That’s easier said than done: Individuals work in silos, and many who employ nannies, house-cleaners, and caregivers don’t see themselves as employers.

The Labor Office may beef up its staff to improve outreach and enforcement, and the Domestic Workers Alliance is hosting workshops in schools, houses of worship, and organizations that work with domestic violence survivors.

In addition, Kligerman said, the alliance built up a support network of more than 50 unions and advocacy groups over the last year as it has pushed for the bill’s passage. (Patrick Eiding, president of the Philadelphia Council AFL-CIO, spoke Thursday in favor of the legislation.) Those groups can reach diverse constituencies throughout the city.

The legislation also requires “referral agencies” — like Care.com, which operates like a job board for nannies and caregivers — to provide both workers and employers information about the contract requirements and make the template agreements available through their website.

Council also voted Thursday to establish a nine-person board to monitor standards and implementation and to continue making recommendations to Council and the mayor’s administration.

Nine states — New Mexico, New York, Hawaii, Connecticut, California, Illinois, Nevada, Massachusetts, and Oregon — and the City of Seattle have passed legislation to protect domestic workers. A nationwide campaign was buoyed by the rising profile of the National Domestic Workers Alliance, as well as the support of Hollywood and the awareness raised by the Oscar-winning Netflix film Roma, about a domestic worker.

Kligerman said there are “major breakthroughs” in the legislation that other cities are already looking at — the paid-time-off system, she said, could be a model elsewhere.

“Workers swung big and fought hard,” she said, “and won everything.”