Nov. 25–San Francisco’s new “Airbnb law” doesn’t take effect until Feb. 1, but opponents already are gearing up to ask voters to approve tougher regulations.

“We want to stop the city’s giveaway of our affordable housing to companies like Airbnb,” said Sara Shortt, head of the Housing Rights Committee of San Francisco, speaking at a press conference outside Airbnb’s San Francisco headquarters on Monday.

Waving signs and chanting slogans, a coalition of housing activists, landlords, unionized hotel workers and neighborhood groups gathered on a South of Market sidewalk Monday to say they believe the new law won’t stop people from turning their homes into ad hoc hotels. Group leaders said they will soon start collecting signatures for a referendum on the November 2015 ballot to place more limits on the practice in San Francisco.

“Renting rooms to tourists is not ‘home sharing’; it’s renting,” said Roger Ritter, president of the West of Twin Peaks Central Council, which represents 20 neighborhood associations and homeowners associations.

Airbnb responded that the new law, passed last month, should be given a chance to work. “We are committed to making San Francisco stronger and we were proud to work on new rules that protect neighborhoods and boost the economy for everyone,” Airbnb spokesman Nick Papas said in a statement.

Rarely enforced

San Francisco has long outlawed short-term rentals in private homes, but rarely enforced the ban until Airbnb’s rapid growth brought the issue to a head. Housing activists say lucrative vacation rentals divert much-needed permanent housing.

After months of contentious hearings and intense lobbying by Airbnb supporters and detractors, the Board of Supervisors last month passed a new law to allow the vacation rentals with some restrictions, including a new city-run registry of hosts. The new law says only permanent San Francisco residents can offer temporary rentals, and caps rentals of entire homes at 90 days a year. Those two prohibitions spurred a lawsuit this month from Airbnb competitor HomeAway, which says the new law discriminates against its business model. Meanwhile, Airbnb opponents said the city won’t be able to enforce the law, as it won’t know whether or not hosts are home during guest stays, meaning all properties can essentially be rented year-round.

Airbnb opponents previously collected signatures for a November 2014 ballot initiative, but decided to defer it while the supervisors hammered out their own law.

Registration system

The groups said they don’t yet have language for their proposal, but it will include a “transparent” registration system (the supervisors’ law keeps the host registry private), and a blanket limit on how often rentals can be offered, whether or not the host is present. To qualify for the ballot, measures require 9,700 valid signatures, which must be submitted by early July.

Airbnb started collecting and remitting San Francisco’s 14 percent hotel tax as of Oct. 1. At Monday’s press conference, the groups hammered on the point that the company should pay back taxes, which they peg at $25 million. They said a back-taxes requirements will also be part of their ballot proposal.

“We are already engaged in a formal process with the Treasurer’s office regarding back taxes, and we are eager to discuss a resolution,” Airbnb’s Papas said. “We look forward to resolving this matter in the spirit of this balanced new law.”

Carolyn Said is a San Francisco Chronicle staff writer. E-mail: [email protected] Twitter: @csaid