California Code, Government Code - GOV § 23254

(a) If privately owned property and no publicly owned property is proposed to be transferred, further proceedings shall not be taken if protest is made by private owners of one-half of the value of the uninhabited territory proposed to be transferred.  The value given such property for protest purposes shall be that shown on the last equalized assessment roll if the property is not exempt from taxation.  If the property is exempt from taxation, its value for protest purposes shall be determined by the county assessor in the same amount as he would assess such property if it were not exempt from taxation.

(b) If privately owned property and publicly owned property are proposed to be transferred in the same proceeding, further proceedings shall not be taken if protest is made by public and private owners of one-half of the value of the uninhabited territory.  The value given privately owned property shall be determined pursuant to subdivision (a) of this section.  The value given publicly owned property for protest purposes shall be determined by the county assessor in the same manner as is provided in subdivision (a) of this section for privately owned property, exempt from taxation.

(c) The value for protest purposes to be given property held in joint tenancy or tenancy in common shall be determined by the commission in proportion to the proportionate interest of the protestant in such property.

(d) When property is subject to a written recorded agreement to buy, the purchaser under the agreement may protest and the seller may not even though he is shown as the owner on the last equalized assessment roll.

Determinations of the value of publicly owned property, or privately owned property exempt from taxation by the county assessor for protest purpose shall be obtained from the assessor by the protestant and submitted to the commission with the written protest.