A new report by the Budget and Legislative Analyst Office states what many have long been arguing about Airbnb and other short-term rental sites. They’re decreasing the amount of available permanent housing in San Francisco.

The independent agency’s report also recommends several policy options to restrict short-term rental companies’ impact. For one, companies like Airbnb should turn over address and booking information of its many hosts so that the city can enforce restrictions.

Using data scraped from Airbnb’s site, the report estimates that between 5,249 and 6,113 listings exist in San Francisco. These units could be responsible for taking between 925 and 1,960 long-term rental units off the market. Based on the number of vacant units available for rent in the most recent survey, that impacts amounts to as much up 23 percent of the rental market citywide. In the Mission, Airbnb listings are estimated to consist of up to 29 percent of the rental market.

“We’ve known short-term rentals will impact the housing market in San Francisco, this report proves this is happening” said District 9 Supervisor David Campos at a press conference Thursday following the report’s release. His office had requested the report but said he thought the numbers were conservative, given that Airbnb had not shared any information other than what’s publicly available on their site.

“By example of New York, the numbers are likely to be much higher,” said Campos. “When New York finally subpoenaed Airbnb for data, the numbers were greater than anything previously seen.”  So far San Francisco has not done this and Airbnb has not volunteered any information.

The report also makes clear what is obvious from a casual glimpse at Airbnb listings. It’s significantly more profitable to rent to short-term vacationers than long-term renters. In some neighborhoods, a building owner can earn an average of as much as $2,000 more a month in short-term rental revenue than they would renting to long-term tenants, according to the report.

Thursday’s press conference was held outside the former apartment of Susan Whetzel at 18th and Church. After living in the apartment for 11 years, Whetzel was evicted and now all three units in her old building are available on Airbnb. She last paid $1,700 a month, now her old unit rents for $250 a night on Airbnb.

Whetzel isn’t alone. The report states that the neighborhoods with the most evictions also have the most Airbnb listings.

Chart by the San Francisco Budget and Legislative Analyst.

Chart by the San Francisco Budget and Legislative Analyst.

Since San Francisco passed legislation in October 2014 legalizing and regulating short-term vacation rentals, city leaders have stated that the law is unenforceable and needs fixing—this includes the Board of Supervisors Planning Commission, and Mayor Ed Lee. About 500 properties have been registered after the city made it a legal requirement to do so, but Airbnb alone has up to 6,000 listings in San Francisco.

Several potential fixes to the measure are in the works, and the Board of Supervisors Land Use and Economic Development Committee is likely to vote on amendments next week. Legislation proposed by Campos, along with Supervisors Eric Mar and John Avalos, is the most stringent.

For one, Campos wants to restrict short-term rentals to 60 calendar days. The law passed in 2014 currently restricts hosts to renting out their property for than 90 days when no host is not present, but if a host is present there is no cap. Legislation supported by Mayor Lee and Supervisor Mark Farrell would change this to a blanket 120 days, and would create a new city office for enforcement.

According to the legislative analyst’s report, the fewer days a property owner is able to use short-term rental services, the more property owners are likely to convert their vacation properties to long-term rental housing.

The report predicts that due to the shift in profitability the 120 night cap—if followed by all hosts— would only reduce the number of Airbnb units by 7 percent. A 90 night cap, would decrease the number of listings by 15 percent. A 60 night cap, would decrease listings by an estimated 27 percent.

“Casual renters will not be effected,” said Campos Thursday of the legislation he endorses. “This is about entire homes being taken off the housing market, we need to prevent that.”

The report differentiated between casual hosts, those who generally only rent out an extra room or their entire home when they’re out-of-town, and commercial hosts, those who rent out entire apartments for a substantial portion of the year—defined as over 58 days. It found that a likely 68 percent of Airbnb hosts are casual ones. Campos’ legislation would take aim at commercial hosts.

“We need to put a check on these hoteliers who are gobbling up the city,” said Sara Shortt, executive director of the Housing Rights Committee, at Thursday’s press conference. “We are losing people from San Francisco because of Airbnb.”

For any of the legislation to be enforced, Campos says that Airbnb and other companies needs to turn over their data about which units are being listed and for how many nights a year—something Airbnb has been resistant to doing and the Planning Commission has voted not to require the company to do so. The company says it won’t hand over the information due to concerns about privacy. Unlike Campos’ legislation, measures proposed by Farrell and Mayor Lee would not require Airbnb to turn over its host information.

As part of its recommendations, the report suggests the Board of Supervisors should enact legislation requiring that hosting sites like Airbnb turn over their book information on a quarterly basis.

“Internet commerce is a universal part of so many Californians’ lives, and sharing economy platforms like Airbnb have a duty to protect the private data of our community,” wrote Airbnb spokesperson David Owen in a recent blog post. “Lawmakers have a responsibility to protect their constituents’ important privacy interests.”

“The fact of the matter is that confidentiality will be protected… small businesses provide confidential information to the city all the time, and that information is kept confidential,” said Campos. “Unless we see their data, enforcement is not going to happen.”

For tenants like Whetzel, who is in the midst of a lawsuit for wrongful eviction with her former landlord Peter Louie, regulating the short-term rental economy earlier could have kept her from having to move.

“I don’t think I’ll be able to find another place,” said Whetzel, who’s currently staying at her next door neighbor’s house. “I see tourists regularly having parties in my old backyard. It’s sad, that used to be my home.”

See the entire report below:

City Budget and Legislative Analysis Report on Short-term Rentals