California Code, Government Code - GOV § 66412.7

A subdivision shall be deemed established for purposes of subdivision (d) of Section 66499.30 and any other provision of this division on the date of recordation of the final map or parcel map, except that in the case of (1) maps filed for approval prior to March 4, 1972, and subsequently approved by the local agency or (2) subdivisions exempted from map requirements by a certificate of exception (or the equivalent) applied for prior to such date and subsequently issued by the local agency pursuant to local ordinance, the subdivision shall be deemed established on the date the map or application for a certificate of exception (or the equivalent) was filed with the local agency.