(Amended by Ordinance No. 176955, effective October 9, 2002.) It is unlawful for any plumber or other person to make connections, installations, replacements, extensions, or repairs to any City water service pipe, or to connect one service pipe with another service pipe, or extend a pipe from one building to another building, or to turn water on or off at any premises without having first obtained permission in writing from the Administrator or Chief Engineer. Such changes may require the installation of an approved backflow prevention assembly, as detailed in Section 21.12.320 "Contamination of the City Water Supply and Requirements for Backflow Protection." After the issuance of a permit to a plumber or other person authorized by the plumbing inspector to do plumbing work, the permittee shall make a report in writing to the Plumbing Division of the Bureau of Development Services of all connections, attachments, and extensions made in accordance with the permit within 3 days after completion of work.