All yards, paved ramps, areas and courts must be drained and sewer connected, such as gasoline or oil service stations and buildings of similar nature or construction. Tenement-houses and lodging-houses must have the paved yards, ramps, areas and courts drained into the sewer, and under no circumstances shall surface or storm water be allowed to drain over walks or driveways. These drains, when sewer connected, must have connection not less than four inches in diameter. They should be controlled by one trap,--the leader trap, if possible.
53 P.S. § 4616