A new proposal designed to give San Francisco tenants increased protections against evictions became law Friday afternoon when Mayor Ed Lee returned the legislation unsigned, despite earlier fears that he would veto it.

“The [housing] crisis is so acute, and the anxiety and reality of eviction and displacement real for so many, that we must take unprecedented steps to help,” said Mayor Lee in a letter sent to the Board Friday evening. “This is why I am allowing this legislation to become law, despite a provision that I believe creates a significant intrusion into certain fundamental rights of small property owners.”

That provision, which passed unanimously at the Board of Supervisors two weeks ago, prohibits landlords from evicting tenants for adding roommates up to the legal limit. The law also prevents evictions for nuisance violations like hanging laundry and for living in illegal units, forbids raising rent on units for following any no-fault eviction, and instructs landlords to provide multilingual information for tenants facing eviction.

“With this victory, thousands of tenants have a fighting chance to stay in their homes,” said Sara Shortt, executive director of Housing Rights Committee of San Francisco, in a press release. “This legislation is crucial to stemming the tide of sham evictions and abuse of tenants that we see on a regular basis.”

The proposal garnered controversy, however, when property owners lobbied the mayor this week, saying they feared the provision left them with no control over who could live in the building and how many people could be added by tenants. If Lee had vetoed the proposal, its unclear whether the Board would have been able to quash his challenge, since a vote on just the roommate provision passed 7-4 and eight supervisors are needed to override a veto.

Ivy Lee, a legislative aide to Supervisor Kim, said many of their concerns were based on “misconceptions.” The legislation, she said, only allowed additional roommates up to housing code limits and that tenants must approve new roommates with their landlords. She also said property owners were confused about the cap on rent increases following a no-fault eviction, thinking it was indefinite. The time period is five years, she said.

“Concerns were raised by small property owners,” she said. “[The Mayor] was trying to figure out if their concerns were valid.”

It seems he relented, though not before noting his disapproval with the roommate provision in his letter to the Board, saying it “does not reflect the right approach when it comes to property owners’ rights.”

Still, returning a legislation unsigned was largely a symbolic measure for the Mayor, as the proposal is now law and will be implemented by the city.

“There was nothing in our legislation that was objectionable enough to warrant an entire veto,” Supervisor Kim’s aide said.

There’s still work to be done, Kim’s aide said. Their office is looking into making the Rent Board more accessible to residents with limited English ability, and opening it up as a resource for both tenants and property owners. She said a lot of unnecessary litigation can be prevented if both tenants and landlords have the right information.

“Not every tenant is a victim, and not every landlord is villain,” she said. “It doesn’t work like that.”