Va. Code § 15.2-1217
Any county may regulate the emission of smoke and the methods of firing and stoking furnaces and boilers and may charge such reasonable fees for the issuance of permits and the performing of inspections as the governing body may from time to time fix. However, counties shall not apply or enforce such regulations in incorporated towns which have in force ordinances prescribing equal or greater standards in regulating the construction, maintenance and repair of buildings and other structures, the installation, maintenance, operation and repair of plumbing, electrical, heating, elevator, escalator, boiler, unfired pressure vessel and air conditioning installations in or appurtenant to buildings and structures, the emission of smoke, the construction, installation and maintenance of fuel-burning equipment, and the methods of firing and stoking furnaces and boilers, and the light, ventilation, sanitation and use and occupancy of buildings.
Va. Code § 15.2-1217