California Code, Government Code - GOV § 66451.195

(a) Counties more than 20,000 square miles in size shall have until January 1, 1990, to record a notice of merger for parcels of 4,000 square feet or less prior to the time of merger, which were merged prior to January 1, 1984, and for those parcels no parcel merged prior to January 1, 1984, shall be considered merged unless the notice of merger has been recorded prior to January 1, 1990.  Counties recording notices of merger pursuant to this subdivision shall comply with the notice requirements of Section 66451.19.

(b) This section shall not be applicable to any parcels or units which meet the criteria of subdivision (a) but which were transferred, or for which the owner has applied for a building permit, during the period between January 1, 1986, and the effective date of this section.