Cal. Gov. Code § 51295
When any action in eminent domain for the condemnation of the fee title of an entire parcel of land subject to a contract is filed, or when that land is acquired in lieu of eminent domain for a public improvement by a public agency or person, or whenever there is any such action or acquisition by the federal government or any person, instrumentality, or agency acting under the authority or power of the federal government, the contract shall be deemed null and void as to the land actually being condemned, or so acquired as of the date the action is filed, and for the purposes of establishing the value of the land, the contract shall be deemed never to have existed.
Upon the termination of the proceeding, the contract shall be null and void for all land actually taken or acquired.
When an action to condemn or acquire less than all of a parcel of land subject to a contract is commenced, the contract shall be deemed null and void as to the land actually condemned or acquired and shall be disregarded in the valuation process only as to the land actually being taken, unless the remaining land subject to contract will be adversely affected by the condemnation, in which case the value of that damage shall be computed without regard to the contract.
When an action to condemn or acquire an interest that is less than the fee title of an entire parcel or any portion thereof of land subject to a contract is commenced, the contract shall be deemed null and void as to that interest and, for the purpose of establishing the value of only that interest, shall be deemed never to have existed, unless the remaining interests in any of the land subject to the contract will be adversely affected, in which case the value of that damage shall be computed without regard to the contract.
The land actually taken shall be removed from the contract. Under no circumstances shall land be removed that is not actually taken for a public improvement, except that when only a portion of the land or less than a fee interest in the land is taken or acquired, the contract may be canceled with respect to the remaining portion or interest upon petition of either party and pursuant to the provisions of Article 5 (commencing with Section 51280).
For the purposes of this section, a finding by the board or council that no authorized use may be made of the land if the contract is continued on the remaining portion or interest in the land, may satisfy the requirements of subdivision (a) of Section 51282.
If, after acquisition, the acquiring public agency determines that it will not for any reason actually locate on that land or any part thereof, the public improvement for which the land was acquired, before returning the land to private ownership, the public agency shall give written notice to the local governing body responsible for the administration of the preserve, and the land shall be reenrolled in a new contract or encumbered by an enforceable deed restriction with terms at least as restrictive as those provided by this chapter. The duration of the restriction shall be determined by subtracting the length of time the land was held by the acquiring public agency or person from the number of years that remained on the original contract at the time of acquisition.
Ca. Gov. Code § 51295