Lyon County, NV Fence Regulations: Retaining Walls (2026)

Under Lyon County Code section 15.240.04, an application for a mass grading permit, required whenever site grading precedes a non-residential building permit or otherwise disturbs the land under sections 15.240.01 and 15.240.02, must include a grading plan showing 'the elevations for top and toe of slopes with slope steepness shown' together with a minimum two-foot property line or fence setback from the top and toe of any slope. The same subsection requires that any retaining wall over four feet in height have engineering calculations included with the grading permit submission, so a homeowner building a tall retaining wall as part of a graded pad cannot rely on standard plans alone.

The grading plan must also tie proposed contours into existing ground elevations extending fifty feet beyond the site's lot lines, and show cut-and-fill quantities and on-site and off-site storm drainage improvements as required by the County Engineer. Work grading under fifty cubic yards is exempt from the mass grading permit entirely under section 15.240.03, which would cover many small residential retaining walls built without a broader grading project. Larger walls tied to graded building pads, however, fall under this permit and its four-foot engineering trigger.

This chapter applies only in unincorporated Lyon County communities such as Dayton, Silver Springs, Stagecoach, Mound House and Smith Valley; Fernley and Yerington regulate retaining walls under their own separate building codes.