(a) The county mayor and four (4) members of the county legislative body appointed by the county mayor of the county in which any commercial facility is located may accompany the department upon any site investigation or monitoring inspection.
(b) The county legislative body of the county in which any commercial facility is located may, by a majority vote of the members to which it is entitled, require that independent monitoring tests be conducted. Such tests shall be conducted by a laboratory which is certified to conduct tests for safe drinking water by the department or the federal environmental protection agency (EPA) under the authority of the Safe Drinking Water Act. All such tests shall be paid for by such county.