County Radon Testing Requirements: Map describing counties that require radon testing. Mandatory Radon Testing Requirement for State Licensed or Regulated Facilities in Single Family Home and Duplex 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 counties where testing is required are: Alachua Brevard Charlotte Citrus De Soto Duval Gadsden Gilchrist Hardee Hernando Highlands Hillsborough Indian River Jackson Jefferson Leon Levy Manatee Marion Martin Nassau Osceola Polk Putnam Sarasota Seminole Sumter Suwannee Union Volusia Walton