CA Gov't Code Section 66499.16

Subdivided real property may be reverted to acreage only if the legislative body finds that:

(a)

Dedications or offers of dedication to be vacated or abandoned by the reversion to acreage are unnecessary for present or prospective public purposes; and

(b)

Either:

(1)

All owners of an interest in the real property within the subdivision have consented to reversion; or

(2)

None of the improvements required to be made have been made within two years from the date the final or parcel map was filed for record, or within the time allowed by agreement for completion of the improvements, whichever is the later; or

(3)

No lots shown on the final or parcel map have been sold within five years from the date such map was filed for record.