Every public garage or service station or other structure having
a water supply, either of a temporary or permanent character, used
for the housing, sale or repair of automobiles or in which automobiles
are washed, cleaned or repaired, shall be provided with a means of
drainage for the floors and repair pit in such a manner as will prevent
the flow of drainage therefrom over streets, alleys or paved approaches.
The drainage from the floors and the repair pit shall be conducted
to an intercepting pit, which shall be ventilated by extending a ventilating
pipe of at least four inches in diameter to at least one foot above
the roof, and it shall be provided with an air inlet open to the outer
air. The intercepting pit shall be of a design approved by the Plumbing
Inspector or other designated officer and shall be watertight, built
of brick laid in cement mortar or concrete, and shall be so arranged
as to intercept all oils, gasoline or other fluids, as well as sand,
silt or other solids, for the purpose of excluding the same as from
the sewer system. It shall be provided with one or more twenty-four-inch
cast-iron manholes and covers, which shall be so located as to be
easily accessible for cleaning.