California chapter 7 bankruptcy homestead exemption: Single person gets 75k. Does debtor automatically get the 100k when married

Yes, so long as you are married and both you and your spouse are living together in the homestead, you automatically are entitled to the $100k exemption. Circumstances where you would not be entitled to the $100k exemption would be, for example, if you were not part of a "family unit." In other words, if you were not married and the other person living with you was not related to you, or if you are married but not living in the homestead with your spouse and the other person living with you was not related to you or your spouse. There are also some limitations on how far removed a person can be and still be considered related for purposes of the "family unit" criteria.

I concur with my colleagues and add that the exemption amount is determined at the date of filing. If single when filing, and later marries during the BK, the homestead exemption does not increase.