Except as provided by Section 158.14 of this chapter, a plumbing permit shall be issued only to a licensed plumbing contractor. If the Building Inspector determines that the plumbing installation, repair, or alteration as proposed in an application complies with the Uniform Plumbing Code and with all other applicable statutes and regulations, said officer shall issue to the applicant a written plumbing permit authorizing the proposed work. A plumbing permit shall state the name of the person to whom it is issued, the location of the premises where the proposed work is authorized, the name of the owner of said premises and a general description of the plumbing installation, repair or alteration which is authorized and it shall be signed by the Building Inspector. Permits shall become invalid unless the work on the site authorized by such permit is commenced within 180 days after its issuance, or if the work authorized on the site by such permit is suspended or abandoned for a period of 180 days after the time the work is commenced. In addition, all work authorized by such permit must be completed within two years for commercial structures and one year for residential structures.