For the tenants of one run-down South Seattle apartment building, living alongside rats, roaches, and broken heaters had been bearable while they were paying $550 a month in rent. That changed when they got a notice that their rent would soon be double that—$1,150 or more.

"People need a new location," said Sahro Farah, who lived with her five children in the building on Rainier Avenue South, during a press conference called by Seattle City Council member Kshama Sawant. "This location—[there is] no safety."

Sawant had gathered Farah and other tenants at City Hall last fall to draw attention to the conditions in their apartments, rent increases demanded by their landlord, and Sawant's proposed solution. She named it the "Carl Haglund law" after Farah's now-infamous landlord.

The law, passed unanimously by the city council on June 6 and supported by the mayor, will temporarily halt rent increases at any building with severe housing-code violations until those violations are fixed. The law takes effect in about a month.

Here's how the law will work: If you're a renter and you receive a notice of a rent increase while living in an apartment or house with serious housing-code violations, you notify your landlord in writing of the problems with the property. If your landlord fails to fix the problems, you can then complain to the city's Department of Construction and Inspections, which will send an inspector to the property. If that inspector finds a violation, they'll notify your landlord that the rent can't be raised until that's fixed. (If you owe the higher rent before the city can get an inspector to your door, you may be eligible for a refund later.)

Not all housing-code violations will trigger the new rule, but the most serious safety-related ones will. Among them: leaky roofs, crumbling or broken foundations or stairs, broken windows, broken heaters, exposed wiring, missing smoke detectors, lack of hot water, rodents, insects, or broken toilets, sinks, or showers. (The full list is on the city's website. Google "Seattle RRIO checklist" and look for the things with an asterisk next to them.) For help, call the city at 615-0808 or the Tenants Union of Washington State hotline at 723-0500.

"It's absolutely appalling that that's what's left for the lowest income people in the city," says Liz Etta, executive director of the Tenants Union. If you have trouble getting a speedy inspection from the city, Etta recommends organizing with your neighbors. "They really do respond when multiple tenants have the same issues," she says.

The Tenants Union knows Haglund well. They say they've heard from tenants of his in the past complaining about code violations at buildings he owns.

Haglund says he thought the building where Sahro Farah lives was in acceptable shape because it passed a city inspection in July, shortly before he bought the building. After tenants planned to protest outside his office, Haglund promised them free rent for a month. The next day, a second city inspection found more than 200 code violations at the building.

Unsurprisingly, Haglund opposes the law nicknamed after him. He says the city should focus on fixing its inspection system instead. "This law isn't going to accomplish what most people think it should accomplish," he says. Developer lobbyist (and sometimes Haglund spokesperson) Roger Valdez goes even further. Valdez claims landlords should be allowed to raise rents at substandard buildings because that's the only way they can pay for improvements. Council members and advocates reject that logic. They say anticipating maintenance costs is a necessary part of running a business.

The fight could end up in court. The Rental Housing Association of Washington, which represents landlords and claims Sawant's law is a form of rent control, has hinted at a possible lawsuit. On the day of the council vote, RHA director Melany Brown said only, "We are having a meeting later this week to discuss options."

The "Carl Haglund law" may be only the beginning. The Tenants Union is advocating for improvements to the inspection law. Members of Sawant's party, Socialist Alternative, continue to call for rent control. And Sawant herself is already working on her next tenant protection: caps on move-in fees. In a city where rents have been rising for years—rents rose between 7 and 9.5 percent over the last year, depending on how you measure—but where state law prohibits rent control, these sorts of protections will be the ongoing focus of the city's populist left.

It's unclear how many renters will benefit from this new law. Etta says the Tenants Union hotline, which takes more than 4,000 calls a year, regularly hears from people facing rent increases and code violations. Until now, they've recommended those renters file a complaint about the code violations and get started finding a new place to live.

"Landlords can increase rents to whatever they want," Etta says. "This protection says, 'No. You cannot do it if you operate a slum.'"