Every public utility engaged in business in the city which shall, after the filing of the map or plat provided for in Section 14.32.020, extend or add to, take away from or reduce its underground system or works herein mentioned, shall, on the first day of January and the first day of July of each year after the filing of the original map or plat, file in an office maintained by it in the city or with the city clerk, an additional or supplemental map or plat showing such changes, in the particulars required by Section 14.32.020. The replacement of an existing underground pipe, conduit or other underground work shall not be deemed a change within the meaning of this chapter. (Ord. 114 NCS §3; prior code §21.11.)