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

California Civil Code section 841 (the Good Neighbor Fence Act of 2013) establishes a statewide rule for shared boundary fences. Subsection (a) provides that 'Adjoining landowners shall share equally in the responsibility for maintaining the boundaries and monuments between them.' Subsection (b)(1) creates a presumption that 'adjoining landowners are presumed to share an equal benefit from any fence dividing their properties' and 'shall be presumed to be equally responsible for the reasonable costs of construction, maintenance, or necessary replacement of the fence.' Subsection (b)(2) requires a landowner who intends to incur costs to give the neighbors at least 30 days' prior written notice describing the problem, the proposed solution, the estimated construction or maintenance costs, the proposed cost-sharing approach, and the proposed timeline. The presumption of equal responsibility can be rebutted by evidence that imposing equal responsibility would be unjust, considering factors such as disproportionate financial burden, whether the cost exceeds the value the project adds, financial hardship, and reasonableness of the project. Napa County's own fence rules in NCC chapter 18.104 govern height, setbacks and permits but do not override Civil Code 841 on cost-sharing between neighbors.