Whenever any excavation for the laying of pipe is made through rock, the pipe shall be laid six inches above the rock bottom of the trench and the space under, around and six inches above the pipe shall be backfilled with clean river sand, noncorrosive soil or one-quarter inch minus gravel. Broken pavement, large stones, and debris shall not be used in the backfill. (Ord. 530 § 2, 2018)