When the plumbing and drainage of existing buildings
and structures is to be revised, plans must be filed, and the new
work or alterations shall be executed in accordance with these rules
and regulations, except if plumbing would cause undue hardship or
damage to the building, in the opinion of the Plumbing Inspector.
The Plumbing Inspector may refer any question arising under this section
to the Plumbing Board.
Permits for plumbing and drainage shall be issued
by the Plumbing Inspector only to master plumbers to whom a certificate
of competency has been issued by the Examining Board of Plumbers of
the city.