14.60.170 Rock and retaining walls.
Walls shall be designed and constructed with due regard for drainage, access, maintenance, impacts to adjacent property, and aesthetics. All walls shall be constructed in accordance with all applicable codes and standards and the following criteria:
(1) Rock walls may be used for erosion protection of cut or fill slopes. The primary function of a rock wall is to protect the slope face from soil erosion and sloughing.
(2) Any wall supporting a surcharge or an exposed wall height of greater than three feet shall require a separate building permit.
(3) All walls shall be provided with a wall drainage system. The wall drainage system shall discharge at an appropriate location:
(a) Wall drains shall be connected to the storm drainage stub provided for the lot, if possible.
(b) Wall drains shall not discharge onto an adjacent downhill property, unless downhill property is a vegetated area that has been set aside as permanent open space or critical area, with approval from the City.
(c) Wall drains shall not discharge onto a steep slope or area susceptible to erosion.
(d) The area above the wall shall be graded to channel water in a direction parallel to the face of the wall until the water can be collected in a pipe or drain, or discharged at an appropriate location.
(4) All walls parallel to a building shall be set back from the building a minimum of five feet. This setback applies to the horizontal space between the wall and the building as measured from the front face of a wall or the cut slope for a wall and the face of the building.
(5) Within the building setback, walls shall not exceed 30 inches in height as measured from the ground surface to the top of the wall.
(6) Walls existing at the time of the ordinance codified in this chapter, if constructed under a valid permit, may be repaired or replaced to their original height.
(7) Walls shall not support earth, other walls, or other structures on an adjacent property.
(8) Walls on a single-family lot may be no higher than four feet. The designer of walls shall also consider the fencing restriction on top of walls in general accordance with CMC 18.35.210.
(9) Walls shall not be located in separate tracts or public rights-of-way for the purposes of circumventing the provisions of this chapter.
(10) Walls shall not be stacked wherein a lower wall is supporting an upper wall, unless the lower wall is designed to do so. Minimum horizontal spacing between rock or retaining walls, as measured from face to face, shall be no less than the thickness of the lower wall plus the height of the lower wall.
(11) Cutting, filling, or constructing walls within storm, water, and sanitary sewer easements is prohibited, unless specific written approval from the utility owner is provided. It shall be the applicant’s responsibility to obtain said approval and to provide a copy to the City.
(12) When preparing a grading plan and designing a roadway, use of a retaining wall to support the roadway shall be considered only after other design options are exhausted. When a roadway must be supported by a retaining wall, the City may require additional building setbacks, easements, or other restrictions and provisions to allow proper maintenance of the wall.
(13) Walls shall not be located or constructed so as to impede travel on a public walkway.
(14) The area above the wall shall be designed and constructed to prevent surface water and debris from flowing over the top of the wall and to allow for access and maintenance to the area above the wall.
(15) The area between the wall and the building shall be graded no steeper than five percent, perpendicular to the face of the wall, for a distance of five feet, for that area located within five feet of the building.
(16) Walls shall not be used to break up a slope or to circumvent the definition of or the restrictions for steep slope hazard areas as described in Chapter 18.65 CMC.
(17) Walls constructed between lots shall be constructed entirely on the downhill side of the property line entirely on one lot, including the wall drainage system. (Ord. 04-19 § 2 (Exh. B); Ord. 06-17 § 5 (Exh. C); Ord. 08-13 § 1 (Exh. A))