How long do I have to file a mechanic lien when homeowner stop payment on check?

The mechancs lien deadline runs from the "completion" of work on the prioject. You likely have 90 days from completion of the project to record your mecahnics lien, but "competion" is a amorphous term and there are exceptions. More information here: https://www.levelset.com/mechanics-lien/california-lien-law-faqs/