(a) Whoever makes any excavation shall, at his or their own expense, properly guard and protect the same so as to prevent the excavation from being or becoming dangerous to life, limb or property.
(b) Whoever makes any excavation below the established grade shall prevent the adjoining soil from falling in. When any excavation is carried to a depth of nine feet or less below the established grade, the owner or owners of any adjoining or contiguous wall or walls, structure or structures, which may be affected by the excavation, shall reinforce it if required and so support it by proper foundations that it or they shall be and remain as safe as before the excavation was commenced.
(c) When an excavation for any purpose shall be carried to a depth of more than nine feet below the established grade, the foundations of all adjoining buildings shall be extended to the full depth of nine feet by the owner thereof, as provided heretofore. The person or persons causing the excavation to be made shall, at his or their own expense, so preserve any adjoining or contiguous wall or walls, structure or structures from injury due to that part of the excavation which is more than nine feet below the established grade and support it by proper foundations so that the wall or walls, structure or structures, shall be and remain as safe as before the excavation was commenced.
(d) An excavation may be made, with proper precautions, to the full depth of any existing foundation on an adjoining lot without liability attaching to the person or persons making the excavation. In all cases where excavating is proposed, the owner or owners of all buildings or structures, which may be affected by such excavating, shall be notified in writing, by the person who proposed to excavate, at least thirty days before commencing work. When a permanent excavation is made on any lot, the person or persons causing the excavation to be made shall build a retaining wall to give lateral support to the earth, and the retaining wall shall be carried to the height of the established grade, and be properly protected by a coping and a substantial railing three feet, six inches high with not less than one intermediate rail. The person or persons making the excavation shall build the retaining wall at his or their own expense, except when the excavation extends to a building and is protected thereby and as specifically provided for along lot lines. (Ord. 17-73. Passed 5-8-73.)