Any county, city or town authorized to levy and collect consumer utility taxes as provided in § 58.1-3814 may levy such taxes upon and collect them from the occupant or lessee of any premises, title to which is held by (i) a person whose property is tax exempt under Chapter 36 (§ 58.1-3600 et seq.) of this title, or (ii) by a person who is exempt from license taxation by virtue of § 58.1-2508. Such taxes shall be applied to the utility services purchased by such person and furnished at such premises for the use and benefit of such occupant or lessee. Such taxes may be fixed at a specific amount per rental unit or other base or measured in some other manner as the county, city or town levying such taxes may prescribe. This section shall not be construed to empower any county, city or town to impose such taxes upon (i) the Commonwealth or any of its political subdivisions or agencies of either, or (ii) the federal government or any of its agencies, or (iii) any person who by law is exempt therefrom.