The next big test of Portland City Hall's ability to compel "sharing economy" companies to share data is less than a month away.

Portland officials say Airbnb and other short-term rental companies have until Feb. 20 to begin posting the addresses and city permit numbers of their hosts—most of whom have not yet undergone the city's safety inspection.

Portland revenue division director Thomas Lannom tells WW he will send letters to short-term rental companies this week informing them they must post the information and begin collecting lodging taxes.

"The letter will advise them of the new requirements that begin on February 20 and ask them to come into compliance," Lannom says. "Any actions after that will depend upon the reactions of the individual companies."

City Council last week passed an ordinance that will fine online rental marketplaces $500 each time a host advertises a rental without posting a city permit number.

Those companies—including Airbnb, HomeAway, TripAdvisor and FlipKey—have lobbied against the city using their data to force hosts to get safety inspections. City officials say they need the information to catch scofflaws and keep visitors safe.

A lot of hosts will need to get permits quickly: The most recent figures from the Bureau of Development Services show just 137 hosts have applied for a city permit. That's about 8.5 percent of the 1,600 hosts estimated to be operating in Portland.

The deadline sets up the latest showdown between Portland City Hall and sharing-economy giants reluctant to offer data to officials. Portland is also seeking company data from Uber as part of a deal to legalize its ride service here.

Lannom tells WW the city has not yet set a budget for enforcing its new rules if Airbnb and other companies don't comply.

On Friday, Mayor Charlie Hales told the Mayors Innovation Conference in Washington, D.C., that Portland officials are being flexible while regulating Silicon Valley companies.

"We're not a schoolmarm, wagging our fingers," Hales said in his presentation. "We're adopting regulations for when things don't work out."