Can Court Papers Be Served by Mail?

Sometimes. Whether mail works depends on what is being served and where. Opening papers (the summons and complaint) can be mailed only in specific ways; most papers served after a case has started can be mailed. This article covers California and the federal courts; other states differ.

A summons by mail in California

Notice and acknowledgment. A summons may be served by first-class mail if the envelope holds the summons, the complaint, two copies of a notice and acknowledgment of receipt, and a postage-paid return envelope addressed to the sender (Code of Civil Procedure section 415.30(a)). Service is complete on the date the person signs the acknowledgment, if it is then returned (section 415.30(c)). The form is POS-015. Full detail: Notice and Acknowledgment of Receipt in California.
If it is not returned. A person who does not sign and return the acknowledgment within 20 days of mailing can be ordered to pay the reasonable expenses of serving them another way, unless there is good cause (section 415.30(d)).
Outside California. A person outside the state may be served by first-class mail requiring a return receipt; service is complete on the 10th day after mailing, and the proof must include evidence of actual delivery, such as a signed return receipt (sections 415.40 and 417.20(a)).
The mailing step of substituted service. Substituted service includes mailing a copy after the papers are left with an adult. Starting January 1, 2027, that mailing may be by first-class mail, Priority Mail with tracking, or Certified Mail with return receipt requested (section 415.20, as amended).
Small claims. The court clerk may mail the claim and order to the defendant by any form of mail that provides a return receipt (section 116.340(a)(1)).

Papers after the case has started

Many papers other than the summons may be served by mail to the address the person last gave on a filed document. Service is complete when mailed, but response deadlines are generally extended by 5 calendar days within California, 10 days to or from another state, and 20 days outside the United States (section 1013(a)).

In federal court

A plaintiff may mail a defendant a request to waive formal service. The defendant gets at least 30 days (60 if outside the United States) to return the waiver, and a U.S. defendant who refuses without good cause must pay the later costs of service (Rule 4(d)).

Other states

Some states allow certified-mail service of a summons; others do not. See process serving by state.

Legal Hub Group arranges process serving for law firms in every state, and mails papers for anyone through service by mail. Representing yourself and need papers handed over in person? Our sister company Famous Legal Services serves papers for individuals.

This is general information, not legal advice.

Questions

Can a summons be mailed in California?

Yes, by the notice-and-acknowledgment method: the summons and complaint are mailed first-class with two copies of the acknowledgment and a prepaid return envelope, and service is complete when the person signs the acknowledgment and returns it (Code of Civil Procedure section 415.30).

What if the person ignores the mailed acknowledgment?

Then service is not complete by that method and the papers must be served another way. If it is not returned within 20 days of mailing, the person can be ordered to pay the reasonable expenses of that other service unless there is good cause (section 415.30(d)).

Can someone in another state be served by mail?

California allows service on a person outside the state by first-class mail requiring a return receipt, complete on the 10th day after mailing (section 415.40). The proof must include evidence of actual delivery, such as the signed return receipt (section 417.20).