Williamson County, TN Fence Regulations: Retaining Walls (2026)

04(D)(14) of the Zoning Ordinance places responsibility for a retaining wall on the property owner: the owner or a representative must ensure the wall is properly designed and constructed, and the owner alone is responsible for its ongoing maintenance and repair. Retaining walls cannot be built within the public right-of-way or in any area later dedicated for right-of-way, and every wall must sit back from the property line by at least five feet or by the total height of the wall, whichever distance is greater, so a six-foot wall needs a six-foot setback even though the flat minimum is five.

Once a wall reaches four feet in height, the property owner must obtain a Zoning Certificate before building, and the application must include three categories of engineering documentation: a plan sheet showing existing and proposed contours, drainage features, buildings, property lines, the proposed wall location, easements, parking and streets; a typical cross-section detailing wall and footing dimensions, backfill slopes, finished grade, steel reinforcement, weep holes and subsurface drainage; and engineering calculations covering concrete and steel strength, soil parameters, surcharges, bearing pressure, and safety factors for bearing capacity, overturning and sliding.

That design work must be prepared and sealed by a professional engineer licensed in Tennessee who has the education and experience to protect public safety and who retains complete control over the design and calculations, including an evaluation of global slope stability both above and below the wall. The County is explicit that approving the plans creates no liability on its part: Williamson County does not assume responsibility or liability resulting from approval of the retaining wall plans or calculations. Walls under four feet skip the engineering submittal but still owe the setback and right-of-way restrictions.