Cal. Gov. Code § 66411

Regulation and control of the design and improvement of subdivisions are vested in the legislative bodies of local agencies. Each local agency shall, by ordinance, regulate and control the initial design and improvement of common interest developments as defined in Section 4100 or 6534 of the Civil Code and subdivisions for which this division requires a tentative and final or parcel map. In the development, adoption, revision, and application of this type of ordinance, the local agency shall comply with the provisions of Section 65913.2. The ordinance shall specifically provide for proper grading and erosion control, including the prevention of sedimentation or damage to offsite property. Each local agency may by ordinance regulate and control other subdivisions, provided that the regulations are not more restrictive than the regulations for those subdivisions for which a tentative and final or parcel map are required by this division, and provided further that the regulations shall not be applied to short-term leases (terminable by either party on not more than 30 days’ notice in writing) of a portion of the operating right-of-way of a railroad corporation as defined by Section 230 of the Public Utilities Code unless a showing is made in individual cases, under substantial evidence, that public policy necessitates the application of the regulations to those short-term leases in individual cases.