Legal Question in Real Estate Law in California

In almost every case, a retaining wall is not located "between" two properties. A retaining wall is located on one property or the other. You would need a survey of your property and/or your neighbor's to determine the location of the property line, and the location of the wall in relation to the property line.

I disagree with Mr. Collins.

First of all, a retaining wall is an engineering term. It is only a legal term when it is incorporated into local building codes. These codes are more common in urban areas than they are in rural areas. The fact that a wall may be retaining soil behind it does not make it a retaining wall. True retaining walls are engineered and constructed to provide drainage and strength to resist lateral forces from soil retained behind the wall.

Some people see a wall and build improvements on their property that causes problems for downslope neighbors. Contrary to what Mr. Collins states, these are often near or on the borders of the adjoining properties. (No on complains about a retaining wall wholly on some neighbor's property that is retaining a flower bed in front of their house.) The law that is applied in these situations is an amalgamation of contract law, trespass and nuisance law, and the doctrine of adjacent and lateral support.

It is true that the general rule is that the wall belongs to the landowner upon which it wholly sits. But this does not resolve a retaining wall problem, which should be thoroughly reviewed by a competent attorney in this field.