回复：加州无争议离婚半年等待期从何时算起？

This is defined in Fam Code 2339. The six month period begins to run on the date when copies of petition and summons have been served or the date when the respondent appears in court, whichever is earlier.

Served means service of process. The petition and summons must be served to the respondent by a third party who is over 18 years old. Keep a record of the proof of service form FL 115 in your record.