County Radon Testing Requirements: Map describing counties that require radon testing. Mandatory Radon Testing Requirement for State Licensed or Regulated Facilities in Large Buildings. Daycare facilities in the following counties should check with their local licensing agent to find out if they are required to test for radon: Sarasota, Brevard, Broward, Hillsborough, Pinellas, Palm Beach. The text Counties where testing is required are: Alachua Brevard Broward Calhoun Charlotte Citrus Columbia Dade De Soto Dixie Duval Gadsden Gilchrist Gulf Hamilton Hardee Hernando Highlands Hillsborough Holmes Indian River Jackson Jefferson Leon Levy Liberty Madison Manatee Marion Martin Nassau Okaloosa Osceola Palm Beach Pasco Pinellas Polk Putnam St. Johns St. Lucie Sarasota Seminole Sumter Suwannee Taylor Union Volusia Walton