When can I start the eviction process? I mailed (via certified mail) the 3 day notice or quit on Thursday (9/13/07) and the tenant received the certified mail notice on Saturday (9/15/07) and as of today they haven't paid the rent or picked up the certified letter. Do I need to hand deliver the 3 day notice or quit instead? Property is located in the sate of CA

No. If your state requires the initial notice to be 3 days, then you can file now.