All pipes shall be laid in alleys or easements wherever possible or at locations by direction of the City Engineer. Gas pipes shall have a lateral clearance of two feet from other utilities, except that in case of sewer pipes, gas pipes shall have a minimum lateral clearance of three feet from them, and all pipes except service pipes shall be laid five feet from the curb line; provided, that, under exceptional circumstances, the City Engineer, with the written consent of the utility involved, may authorize less clearance. Pipes shall have a vertical clearance of 12 inches when crossing another pipe. Pipes shall be laid with a cover of not less than 30 inches and 30 inches below all irrigation and drainage ditches or flumes, except that, under exceptional circumstances, the City Engineer may authorize less coverage. Where a trench is in rock, the depth may be 24 inches if the pipe is properly cushioned by refilling the trench with sand or noncorrosive soil. In the event interference with other subsurface structures makes it impractical to maintain the above depths and clearances, the City Engineer, with the written consent of the utility involved, may permit gas pipelines and mains to be constructed so as to avoid such subsurface structures. [Ord. 4515 § 2, 2021; Ord. 1503 § 25, 1971; Code 1970 § 16.12.250.]