Mayor and Deputy Mayor.

(1) No person other than a licensed plumber shall execute any work described in this Chapter or in Chapter XII of this Act and no person shall permit any such work to be executed except by a licensed plumber: Provided that if, in the opinion of the Commissioner, the work is of a trivial nature, he may grant permission in writing for the execution of such work by a person other than a licensed plumber. (2) Every person who employs a lincesed plumber to execute any such work shall, when so required, furnish to the Commissioner the name of such plumber. (3) Every such person shall, within one month after completion of any such work and before permitting the same or any portion thereof to be filled in or covered over, de­liver or send or cause to be delivered or sent to the Commissioner at his office notice in writing of the completion of such work, accompanied by a certificate in such form as the Commissioner may from time to time prescribe signed by the licensed plumber by whom the same has been executed, who is hereby required immediately upon completion of the work and upon demand by the person employing him to sign and give such certificate to such person, and shall give to the Commissioner all necessary facilities for the inspection of such work: Provided that— (a) such inspection shall be made within seven days from the date of receipt of the notice of completion, and (b) the Commissioner may, within seven days after such inspection, by written in­timation addressed to the person from whom the notice of completion was received and delivered at his address as stated in such notice, or, in the absence of such address, affixed to a conspicuous part of the premises in which such work has been executed— (i) give permission for the filling in or covering over of such work ; or (ii) require that, before such work is filled in or covered over, it shall be amended to the satisfaction of the Commissioner in any particular respect of which it is not in accord with a requisition previously made by the Commissioner or contravenes some provisions of this Act or of the rules or by-laws. (4) No person shall permit any such work to be used as a drain or part of a drain until— (a) the permission referred to in proviso (b) to sub-rule (3) has been received ; or (b) the Commissioner has failed for fourteen days after receipt of the notice of completion to intimate as aforesaid his refusal of permission for the filling in or covering over of such work. Manner of erecting shafts or affixing pipes for ventilation of drains or cesspools.