Except as otherwise provided in any ordinance authorizing an indenture securing revenue bonds issued for construction of the system or a portion thereof, no lot, parcel of land, building or premises now or hereafter used by the City for municipal purposes shall be subject to the sewer charges hereby established, nor shall any water supplied by the municipal waterworks system for extinguishing fires, cleaning fire apparatus or furnishing or supplying water to fire hydrants be used to determine any sewer charge provided in Section 923.02.
(1957 Code § 16-15)