Monument Preservation in Mill Valley, CA

Business and Professions Code section 8771 prohibits destroying a survey monument and requires that, where construction will disturb one, a licensed surveyor set durable reference ties and file a Corner Record or Record of Survey before the work begins, then restore the point afterward. The duty follows the construction, so it lands on the owner and the contractor. In Mill Valley the triggers are the ordinary maintenance of a hillside town: repaving narrow winding streets in place, rebuilding retaining walls inside the right of way, trenching for water, sewer, and undergrounding, storm drain and creek bank repairs, and reconstructing the public stairways that link one street to the next.

The terrain adds a second problem that flatland cities do not have. Slope creep, winter slides, and bank erosion move and bury monuments between projects, so the point shown on a map from the 1970s may be several feet from where it was set, or under a wall built since. That makes the pre-construction search a real search, not a formality, and it makes the reference ties matter: ties placed on stable ground outside the disturbance limits are what allow the point to be reset defensibly after the contractor is gone.

Our Trimble scanner records each monument in its setting, capturing the curb, wall face, pavement joints, stair treads, and adjacent improvements as measured geometry rather than as a photograph, so a reset months later can be checked against how the site actually looked. Corner Records are filed with the Marin County Surveyor at the Department of Public Works in San Rafael, and Records of Survey are recorded by the Marin County Recorder. See monument preservation under section 8771 and our Mill Valley parcel map services.