Only the following person or persons shall construct, repair, alter or remove building sewers or make connections therefrom to a public sewer:
A. 
Regular forces of or a contractor employed by the Superintendent or the city.
B. 
A drain layer who has been issued a sewer permit by the Superintendent to perform the work specified in the sewer permit.
Drain layers as defined in § 191-3A shall conform to the requirements of § 191-19.
It is not the intent of this chapter to restrict the usual work of plumbers or others working in accordance with any plumbing and building codes. Plumbers and others may work on pipes within and not more than five feet outside the walls of any structure, provided that no connection to a public sewer shall be made by such persons without a permit from the Superintendent, irrespective of the distance of said public sewer or the structure in question. All drains and fixtures within structures shall be connected by plumbers and others in conformity with the requirements of this chapter as to what may or what may not be discharged into the public sewers.