POLK COUNTY, Fla. (WTSP) -- The Polk County Tax Collector's office is cracking down on people who don't pay the so-called bed tax when they rent out homes through apps like Airbnb.

The tax, which applies to hotels as well as vacation rentals, is 5 percent of the cost of the stay in Polk County. It is charged in addition to a 7 percent sales tax and is used to promote economic development and tourism.

The county reached a deal with Airbnb earlier this year, so the app company is responsible for paying the county's bed tax. Still, people who rent out their homes using Airbnb, or even just a spare bedroom, are required to report their earnings to the tax collector's office.

Unlike Airbnb, people who use other rental apps and sites have to pay the tax themselves.

The county is making it a priority that the tax gets paid and making sure people who use Airbnb are reporting accurate information to them.

Employees at the tax collector's office are keeping an eye on homeowners they suspect are renting their homes without reporting it. One tell-tale sign, they said, is if the pool at their home has a rules sign listed. Another is if the trash cans are still out by the street several days after collection day.