Notice of Related Cases in California: Form CM-015 and Deadline

To flag a Notice of Related Case in California, file Judicial Council Form CM-015 within 15 days of learning that your civil lawsuit is connected to another case, file it in every pending case listed on the form, and serve a copy on every party in those cases. The duty applies whether the other case is still active, was dismissed, or ended in judgment, and it covers related cases in any California state or federal court. Missing the filing can bring monetary sanctions under Rule 2.30.¹

When Two Cases Count as Related

Rule 3.300 treats civil cases as related when they share at least one of four connections:

The same parties are suing over the same or similar claims.
Both cases arise from the same transaction, incident, or set of facts, producing overlapping legal or factual questions.
Both cases involve claims about, ownership of, possession of, or damage to the same property.
The cases would otherwise force different judges to duplicate substantially the same work.

The definition is broad on purpose. Separate lawsuits by different passengers in one car accident are an easy fit, but so is a contract dispute paired with a fraud claim from the same business deal. The question is practical overlap, not identical pleadings.¹

The 15-Day Deadline

The duty triggers the moment you learn the related case exists. You have to file the notice as soon as possible and no later than 15 days after those facts become known to you. And the obligation does not end after one filing. If you discover another related case months into your lawsuit, a fresh 15-day clock starts from that new discovery.¹

The rule reaches beyond your own courthouse. A related case pending in a different California superior court, or in a federal court anywhere in California, still has to be disclosed. A Los Angeles state plaintiff who finds out about a related case in the Central District of California owes the same notice.¹

Filling Out Form CM-015

Use Judicial Council Form CM-015, “Notice of Related Case,” available on the California Courts website.² The form asks for three things:

Your current case: court name, full case title, and case number.
Each related case, listed in chronological order by filing date, with its title, case number, filing date, the court where it was filed, and its current status (pending, dismissed, or concluded).
Why the cases are related. Checkboxes track the four Rule 3.300 categories. Check every one that applies, and attach a written explanation if the boxes do not fully capture the connection.

List the cases in true chronological order. Filing dates decide which judge reviews the notice: normally, the judge on the earliest-filed case makes the call on relatedness.¹

Filing in Every Case and Serving Every Party

This is where the process departs from an ordinary filing. The completed CM-015 must be filed in every pending case listed on the form, not just your own. Three connected lawsuits means three separate filings of the same notice. You can file through the court’s e-filing portal, in person at the clerk’s office, or by mail.¹

You also have to serve a copy on every party in every case listed. Every plaintiff and every defendant across all the actions gets one. Service can be by mail, personal delivery, overnight courier, or any other method the Code of Civil Procedure allows.

After service, file a Proof of Service with the court. Judicial Council Form POS-040, “Proof of Service—Civil,” is the standard form. Whoever delivered or mailed the notice completes it, declaring when, where, and how service happened. Filing POS-040 puts your compliance on the record.

What Happens After You File

The presiding judge, or a judge the presiding judge designates, reviews the notice. Ordinarily the judge assigned to the earliest-filed case decides whether the cases are truly related. When the group mixes unlimited and limited civil matters, the judge on the earliest-filed unlimited case takes the lead.¹

Other parties have five days after service to file a response supporting or opposing the notice. An opposing response has to explain why the cases are not related or why good cause exists to keep them separate. The deciding judge may also confer with the judges handling the other cases before ruling.¹

If the judge agrees the cases are related, a formal order assigns all of them to a single judge. That order is filed in every pending case and served on all parties. If the judge disagrees, no order issues and each case continues on its own track.¹

Related Is Not Consolidated

A relatedness order moves the cases in front of one judge. It does not merge them. Each case keeps its own number, its own file, and its own schedule. Consolidation, under Code of Civil Procedure section 1048, is a separate step: a judge with related cases on the docket can order the cases combined for a joint hearing or trial when they share common questions of law or fact, weighing efficiency against the risk of prejudice or confusion.³ Filing CM-015 does not trigger consolidation. It just gets the cases to one desk, which is often the practical setup for a later consolidation motion.

When Related Cases Are in Different Counties

Related cases sometimes sit in different superior courts. The judge on the earliest-filed case can informally confer with judges in the other counties and with the parties about joint discovery orders or other coordination. If formal coordination is warranted, noncomplex cases follow the transfer and consolidation procedures under Code of Civil Procedure section 403 and Rule 3.500. Complex cases follow the coordination procedures under Code of Civil Procedure section 404 and the rules beginning at Rule 3.501, which can send a petition to the Chair of the Judicial Council and end with all the cases assigned to a single coordination judge anywhere in the state.¹

Sanctions for Not Filing

Rule 3.300 states the notice as a mandatory duty. If you fail to file without good cause, California Rule of Court 2.30 gives the court broad authority to sanction you. The court can order the non-compliant party or their attorney to pay reasonable monetary sanctions to the court, the other side, or both, and can award the aggrieved party the reasonable expenses, including attorney’s fees and costs, of bringing the violation to the court’s attention.⁴

Beyond formal sanctions, failing to disclose a related case invites inconsistent rulings, duplicated discovery costs, and a credibility problem with the court. When a party should have known and stayed quiet, judges tend to notice.

1
Judicial Branch of California. Rule 3.300 Related Cases
2
Judicial Branch of California. Notice of Related Case (CM-015)
3
Justia. California Code of Civil Procedure Chapter 7 General Provisions
4
Judicial Branch of California. Rule 2.30 Sanctions for Rules Violations in Civil Cases