If, in the opinion of the plumbing inspector, the description of the work in the application is insufficient, two (2) sets of plans in detail must be submitted to the plumbing inspector for approval before a permit shall be issued. When in the opinion of the city engineer, the interests of the city are best served and the proposed work is of such magnitude, he shall require the submittal of such plans and specifications prepared by a registered professional engineer. One set of plans, approved with such corrections noted as may be necessary to comply with this chapter will be returned to the plumber. The plumbing system shall be installed in accordance with such approved plans. No subsequent alterations shall be made in these plans without the written approval of the city engineer. (Ord. No. G-85-17, § 1, (Title 4, § 4), 12-12-85)