CA Prob Code Section 21611

The spouse shall not receive a share of the estate under Section 21610 if any of the following is established:

(a)

The decedent’s failure to provide for the spouse in the decedent’s testamentary instruments was intentional and that intention appears from the testamentary instruments.

(b)

The decedent provided for the spouse by transfer outside of the estate passing by the decedent’s testamentary instruments and the intention that the transfer be in lieu of a provision in said instruments is shown by statements of the decedent or from the amount of the transfer or by other evidence.

(c)

The spouse made a valid agreement waiving the right to share in the decedent’s estate.