The most common real estate litigation between neighbors are boundary disputes between their adjacent properties. Real estate attorneys who deal in neighbor-on-neighbor boundary lawsuits can attest that, of all types of property litigation, boundary litigation can be ugly, hard fought and bitter. Theoretically, these types of lawsuits should be easy to settle. The parties can conduct a survey marking the legal description of the property to determine the true legal boundaries of the property. However, because a man’s house is his castle, litigation between neighbors can be contentious and emotional. Oftentimes the only true winners are the lawyers.
One of the legal principles involved in boundary lawsuits is the “agreed-boundary doctrine”. In general, the legal description of land contained in a deed sets forth the boundaries between the properties. That is to say that there is a legal description recorded with the County on a deed which sets forth the boundaries between properties. This boundary can be ascertained by having a survey done.
The agreed-boundary doctrine is an exception to that general rule. The doctrine provides that when two adjacent owners who are uncertain of the true position of the common boundary between the parcels agree to the true position of the common boundary, mark it on the ground or build it up, and occupy each side for a period equal to the statute of limitations, then such line becomes the boundary. An agreed-upon boundary can also be established when a party relies on the agreement and to change it would cause substantial loss.
The idea behind the doctrine is to allow parties to come to an agreement which prevents future lawsuits. When the doctrine is applied, it is then binding on successors. California law provides that the doctrine may be invoked only under carefully specified circumstances. The elements required to prove title by agreed boundary are  an uncertainty as to the true boundary line,  an agreement between the coterminous owners fixing the line, and  acceptance and acquiescence in the line so fixed for a period equal to the statute of limitations or under such circumstances that substantial loss would be caused by a change of its position.
Interestingly, a properly recorded and publicly available deed which sets forth the boundary description does not necessarily defeat a claim under this doctrine. Since the critical question is the parties’ intent to create a boundary to settle their subjective uncertainty as to the true line, the weight of authority has considered it immaterial that the true line could have been ascertained by a proper survey. It is not required that the true location be absolutely unascertainable. The California Supreme Court confirmed this long-standing rule when it expressly declined “to limit application of the agreed-boundary doctrine to instances in which existing legal records are inadequate to settle a boundary dispute.” The court explained that “such an inflexible rule would risk destabilizing long-standing agreements—made in good faith by coterminous property owners in order to resolve uncertainty as to the location of their common boundaries—that might, for any one of several reasons, be at variance with legal property descriptions or survey results.”
Is a fence an agreed-upon boundary? The mere existence of a fence will not cause a court to infer an agreement without evidence of such an agreement. The fact that a fence is somewhere other than on the true boundary line does not means that the property owners had some uncertainty as to the property boundary or that the fence was intended to resolve any such uncertainty. Even if the fence had existed for many years, this in itself does not satisfy the requirement that there have been some uncertainty to the boundary or that the fence was intended as an agreement as to what the boundary should be. A California court has held that “when existing legal records provide a basis for fixing the boundary, there is no justification for inferring, without additional evidence, that the prior owners were uncertain as to the location of the true boundary or that they agreed to fix their common boundary at the location of a fence.
How do you prove agreement? Practically speaking, this requirement can be difficult to prove in an urban or suburban neighborhood. Prior owners can be hard to track down and even then it seems unlikely that they would have entered into such an agreement. However, it appears that their testimony is required to prove this agreement. In one case, the court held that the requirements of the agreed boundary doctrine were not satisfied where the only testimony about the original fence builder’s intent was from a neighbor who testified that the prior owners “had not engaged in any argument or discussion concerning the boundary line.”
Overall, among residential neighborhoods in urban and suburban metropolitan neighborhoods like Los Angeles, real estate attorneys and their clients will have a hard time relying on the agreed-boundary doctrine. The general rule that the boundary is what the deed says it is will usually apply.