Gov. Code, § 66451.30

Any parcels or units of land for which a notice of merger had not been recorded on or before January 1, 1984, shall be deemed not to have merged if on January 1, 1984:

(a) The parcel meets each of the following criteria:

(1) Comprises at least 5,000 square feet in area.

(2) Was created in compliance with applicable laws and ordinances in effect at the time of its creation.

(3) Meets current standards for sewage disposal and domestic water supply.

(4) Meets slope density standards.

(5) Has legal access which is adequate for vehicular and safety equipment access and maneuverability.

(6) Development of the parcel would create no health or safety hazards.

(7) The parcel would be consistent with the applicable general plan and any applicable specific plan, other than minimum lot size or density standards.

(b) And, with respect to such parcel, none of the following conditions exist:

(1) On or before July 1, 1981, one or more of the contiguous parcels or units of land is enforceably restricted open-space land pursuant to a contract, agreement, scenic restriction, or open-space easement, as defined and set forth in Section 421 of the Revenue and Taxation Code.

(2) On July 1, 1981, one or more of the contiguous parcels or units of land is timberland as defined in subdivision (f) of Section 51104, or is land devoted to an agricultural use as defined in subdivision (b) of Section 51201.

(3) On July 1, 1981, one or more of the contiguous parcels or units of land is located within 2,000 feet of the site on which an existing commercial mineral resource extraction use is being made, whether or not the extraction is being made pursuant to a use permit issued by the local agency.

(4) On July 1, 1981, one or more of the contiguous parcels or units of land is located within 2,000 feet of a future commercial mineral extraction site as shown on a plan for which a use permit or other permit authorizing commercial mineral resource extraction has been issued by the local agency.

(5) Within the coastal zone, as defined in Section 30103 of the Public Resources Code, one or more of the contiguous parcels or units of land has, prior to July 1, 1981, been identified or designated as being of insufficient size to support residential development and where the identification or designation has either (A) been included in the land use plan portion of a local coastal program prepared and adopted pursuant to the California Coastal Act of 1976 (Division 20 of the Public Resources Code), or (B) prior to the adoption of a land use plan, been made by formal action of the California Coastal Commission pursuant to the provisions of the California Coastal Act of 1976 in a coastal development permit decision or in an approved land use plan work program or an approved issue identification on which the preparation of a land use plan pursuant to the provisions of the California Coastal Act is based.

For purposes of paragraphs (3) and (4), “mineral resource extraction” means gas, oil, hydrocarbon, gravel, or sand extraction, geothermal wells, or other similar commercial mining activity.

Each city or county, as applicable, may establish the standards specified in paragraphs (3) to (7), inclusive, of subdivision (a), which shall be applicable to parcels deemed not to have merged pursuant to this section.