What is the rule on service of summons by mail?
California allows service of summons by mail only in a limited, consent-based form under Cal. Code Civ. Proc. § 415.30, and for persons outside California by first-class mail with return receipt under Cal. Code Civ. Proc. § 415.40. The basic rule is that the plaintiff mails the summons and complaint with the required notice-and-acknowledgment form; service is complete only when the defendant signs and returns the acknowledgment. [1][3][4]
Rule on service of summons by mail
1. Within California: notice and acknowledgment
Under Cal. Code Civ. Proc. § 415.30, a summons may be served by mail by sending:
- a copy of the summons and complaint,
- two copies of the notice and acknowledgment form,
- and a postage-paid return envelope addressed to the sender.[1][3]
Service is complete on the date the written acknowledgment of receipt is executed and returned.[1][3][4]
If the recipient does not return the acknowledgment within 20 days, the sender may recover reasonable expenses incurred in serving by another method, absent good cause.[1][3]
2. Outside California: first-class mail with return receipt
Under Cal. Code Civ. Proc. § 415.40, a summons may be served on a person outside the state by sending the summons and complaint by first-class mail, postage prepaid, requiring a return receipt.[5]
Service by this method is deemed complete on the 10th day after mailing.[5]
3. Practical points
California courts summarize the rule this way:
- substituted service is complete 10 days after mailing;
- mail service under § 415.30 is complete when the recipient signs the acknowledgment;
- proof of service for mail service under Cal. Code Civ. Proc. § 415.30 must include the signed acknowledgment.[2][6]
Quick comparison
| Method | Statute | What is mailed | When service is complete |
|---|---|---|---|
| Notice and acknowledgment | Cal. Code Civ. Proc. § 415.30 | Summons, complaint, two acknowledgments, return envelope | When acknowledgment is signed and returned[1][3][4] |
| Out-of-state mail service | Cal. Code Civ. Proc. § 415.40 | Summons and complaint by first-class mail, return receipt requested | 10th day after mailing[5] |
Bottom line
If you mean service of the summons itself by mail in California, the ordinary rule is not simple mailing alone; it requires the notice-and-acknowledgment procedure under Cal. Code Civ. Proc. § 415.30 unless a different statute applies, such as out-of-state service under Cal. Code Civ. Proc. § 415.40.[1][3][5]