Service by Notice and Acknowledgment of Receipt
A great service device often overlooked by lawyers handling service issues is the notice and acknowledgment of receipt of summons and complaint.
The procedure is authorized by Code of Civil Procedure section 415.30 (a). You mustr mail a copy of the summons and complaint, two copies of the notice of acknowledgment nd receipt form; and a postage prepaid envelope along with any additional things such as ADR packages that the specific court may order you to serve on the defendant.
If the defendant signs and returns the acknowledgment, then service is effective that day (30 days to respond). If the defendant does not respond within 20 days- then they become liable for whatever costs Plaintiff incurred in effecting service by some other method-regardless of the outcome (See CCP section 415.30 (d).)