Mariposa County, CA Fence Regulations: Neighbor Fence Rules (2026)

For shared boundary fences in unincorporated Mariposa County, state law fills the gap left by local regulation. The Planning Department states it has no jurisdiction over the placement of a fence in the rural areas of the county and that such matters are civil disputes between neighbors. California Civil Code Section 841, the Good Neighbor Fence Law, controls these situations. It provides that adjoining landowners shall share equally in the responsibility for maintaining the boundaries and monuments between them. Adjoining landowners are presumed to share an equal benefit from any fence dividing their properties and, unless otherwise agreed in writing, are presumed equally responsible for the reasonable costs of construction, maintenance, or necessary replacement of the fence. Before incurring those costs, a landowner must give at least 30 days' prior written notice to each affected adjoining landowner, describing the problem, the proposed solution and cost, the proposed cost-sharing, and the timeline. The equal-cost presumption can be overcome by evidence that splitting costs equally would be unjust, considering disproportionate burden, the effect on property value, and financial hardship. Inside a Town Planning Area, additional setback and Design Review rules may also apply.