Knowing if and when a Notice of Completion (NOC) has been recorded in California is crucial for contractors to determine their lien filing deadlines ; among other things.
Under California law (Cal. Civ. Code §8190), "(a) An owner that records a notice of completion or cessation shall, within 10 days of the date the notice of completion or cessation is filed for record, give a copy of the notice to all of the following persons: (1) A direct contractor. (2) A claimant that has given the owner preliminary notice."
If the owner fails to send notice within that 10 day period, the notice will be ineffective to shorten the time within which that person may record a claim of lien. The moral of the story is to ensure that a CA 20-day preliminary notice is sent out on every project. That way the owner is legally obligated to inform you of the NOC filing.
For further reading, see: Should You Monitor for a California Notice of Completion?