(1) The finished Grade of any Lot in any Subdivision in the City or any parcel to be used for the construction of any Building in the City shall be graded or contoured in such a manner that the Grade differential within three feet of a property line between Lot boundaries (for Lots within a recorded Subdivision) or between adjoining properties (for the perimeter boundaries of a Development site) does not exceed 18 inches of vertical height or a 2 to 1 slope.

(2) Where the Grade differential within three feet of a property line is greater than 18 inches of vertical height, or is in excess of a 2 to 1 slope, the developer shall install either a permanent concrete or masonry wall, a rock retaining wall, or other retaining type walls approved by the Building Inspection Division to provide sufficient lateral support and to control runoff waters from the elevated property. In no case shall fill be brought onto a site or that a site be excavated or graded in such a manner so as to violate the 18-inch Grade differential without the installation of a permanent retaining wall or Structure.

(3) In cases where the developer or property Owner selects to grade the site with a 2 to 1 slope, a mechanism to divert water from adjacent properties shall be used. This mechanism shall be reviewed and approved by the Public Works Department and Building Inspection Division.

(4) Permanent Yard grading for each residential Structure shall provide a minimum (2%) positive slope 10 feet away from the dwelling.

(5) Permanent Yard grading and coordination of yard grading between properties shall be the responsibility of the property Owner.

(6) Any retaining wall within a residential or Commercial Development which has a Grade difference of greater than four feet shall require a building permit from the City Building Inspection Division. Plans for the retaining wall shall be approved by the City Engineer and Building Official, who may impose additional requirements to ensure that water will adequately and safely drain from above and around the subject property.