Labor Code §5400 – 30-Day Notice of Injury

Labor Code §5400 says you must give your employer written notice of a work injury within 30 days after it happens, signed by you or someone acting for you. Two companion sections soften the rule: if your employer already knew about the injury from any source, that knowledge counts as notice (§5402), and late or defective notice does not bar your claim unless the employer was actually misled or prejudiced (§5403).

Section 5400 is the first step in the workers’ comp timeline, and it is easy to confuse with the next one. Telling your employer about the injury is notice under §5400. The DWC-1 claim form is a separate document governed by §5401. For how the claim form works and when it counts as filed, see our page on Labor Code §5401 and the DWC-1 claim form. This page covers the notice rule itself: what it requires, who it applies to, its exceptions and what happens if you miss it.

What Labor Code §5400 says

Section 5400 is one sentence. It says that, except as provided by §§5402 and 5403, “no claim to recover compensation under this division shall be maintained unless within thirty days after the occurrence of the injury which is claimed to have caused the disability or death, there is served upon the employer notice in writing.” The notice must be “signed by the person injured or someone in his behalf,” or, if the worker died, by a dependent or someone on the dependent’s behalf.

Broken into parts, the rule has five elements:

• Thirty days. The clock runs from “the occurrence of the injury.”
• In writing. The statute calls for written notice, not just a conversation.
• Signed. By you, by someone acting for you, or by a dependent in a death case.
• Served on the employer. The text calls for notice “served upon the employer.”
• Subject to §§5402 and 5403. The opening words make the rule yield to employer knowledge and to the no-prejudice rule.

The statute does not prescribe a form or list required contents. In practice, a short note, signed and dated, saying what happened, when, where and which body parts were hurt covers the basics and creates a record for later.

Key fact

Who §5400 covers

The rule applies to anyone who wants to “recover compensation” under the workers’ comp division of the Labor Code. That includes:

• Employees with a specific injury, such as a fall, cut or lifting strain.
• Employees with a cumulative injury or occupational disease that develops over time.
• Dependents bringing a death claim. In that case the notice is signed by a dependent or someone acting for one.

Watch: injured at work in California

Our attorneys explain what your employer must do after a work injury, and what to do in the first 24 hours to protect your claim.

The exceptions: §5402 and §5403

Employer knowledge counts as notice (§5402(a))

Under §5402(a), “knowledge of an injury, obtained from any source,” on the part of the employer, its managing agent, superintendent, foreman or other person in authority, “is equivalent to service under Section 5400.” Knowledge of a claim counts too, if it gives the employer a fair opportunity to investigate. So if your supervisor saw you fall, or you told your foreman the same day, the employer has notice even though nothing was written down.

Late or flawed notice is not automatically fatal (§5403)

Section 5403 says that failing to give notice, or giving notice with a defect or inaccuracy, “is not a bar to recovery” if the proceedings on the claim find that “the employer was not in fact misled or prejudiced” by it. In other words, missing the 30-day mark does not by itself end a claim. The question becomes whether the delay actually hurt the employer, for example by costing it the chance to investigate.

Cumulative injuries and occupational disease

Section 5400 measures 30 days from the occurrence of the injury. For a gradual injury, the Labor Code fixes the date of injury separately: under §5412 it is the date you first suffered disability and knew, or reasonably should have known, that the work caused it. Our §5412 page explains that date. The Division of Workers’ Compensation tells workers to report a gradual injury “as soon as you learn or believe it was caused by your job.”

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What happens if you miss the 30 days

Section 5400 itself contains no penalty and no fine. Its effect is on your claim: without timely notice, a claim cannot be “maintained,” unless §5402 or §5403 applies. Because employer knowledge under §5402 counts as notice, and because §5403 turns on whether the employer was in fact misled or prejudiced, late written notice does not automatically end a claim. Still, the DWC warns that if you don’t report within 30 days, “you could lose your right to receive workers’ compensation benefits.” Prompt written notice removes the argument entirely.

Notice also matters later. If you are laid off or fired and file your claim afterward, one way to qualify under Labor Code §3600(a)(10) is showing the employer had notice under these rules before the termination notice.

Key fact

Deadlines after notice

Event	Deadline or effect	Statute
Injury occurs	Written notice to the employer within 30 days	§5400
Employer gets notice or knowledge of an injury that causes lost time beyond the shift or needs more than first aid	Employer must provide a claim form and notice of potential eligibility within one working day	§5401(a)
Claim form filed	Employer has 90 days to reject liability or the injury is presumed compensable (75 days for injuries and illnesses under the presumptions in §§3212 to 3212.85 and 3212.9 to 3213.2)	§5402(b)
Filing a case with the WCAB	Generally one year; see the §5405 page for when the year starts and what extends it	§5405

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Related sections

Section	What it covers
§5401	The DWC-1 claim form: when the employer must provide it and when it counts as filed
§5402	Employer knowledge equals notice; the 90-day rule for denying a claim
§5403	Missing or defective notice is not a bar unless the employer was misled or prejudiced
§5405	The one-year deadline to file a case
§5412	Date of injury for cumulative trauma and occupational disease
§3600(a)(10)	Extra proof for claims filed after a termination or layoff notice; prior notice is one way to meet it

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How it plays out

💡 Example: Two hypothetical delivery drivers twist a knee unloading the same truck on February 2, 2026. The 30-day notice period under §5400 runs to March 4, 2026. Darnell’s supervisor sees him go down and drives him to urgent care. That is knowledge by a person in authority, so under §5402(a) the employer has notice even though Darnell never wrote anything. Lena tells no one and keeps working until March 20, 2026, 46 days after the injury, when she gives her manager a signed note. Her written notice is 16 days late. Under §5403, the delay is not a bar if it is found that the employer was not in fact misled or prejudiced by it. Whether the employer lost the chance to investigate is the kind of question that decides it. Lena’s claim is not automatically over, but she has handed the employer an argument that Darnell never faced.

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What to do after a work injury

Our DWC-1 form guide walks through the claim form. For notice under §5400:

• Tell your supervisor right away, then follow up in writing the same day if you can. A dated email or text creates a record.
• Say what happened, the date, the place and the body parts affected. Sign and date it.
• Keep a copy and note who received it.
• For a gradual injury, report as soon as you believe the work caused it, even if you are not sure yet.
• Ask for the claim form. Your employer must provide it within one working day after learning of a qualifying injury.

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Frequently asked questions

Does telling my supervisor count as notice under Labor Code §5400?

Yes, in effect. Section 5400 calls for written notice, but §5402(a) makes knowledge of the injury held by a managing agent, superintendent, foreman or other person in authority “equivalent to service under Section 5400.”

Does the notice have to be on a special form?

No form is named in §5400. It requires notice “in writing,” signed by you or someone acting for you, served on the employer. The DWC-1 claim form is a separate requirement under §5401.

Is my claim over if I reported after 30 days?

Not automatically. Under §5403, late or defective notice is not a bar to recovery if it is found that the employer was not in fact misled or prejudiced by it. Employer knowledge under §5402 can also cover the gap.

Is the 30-day notice the same as the one-year deadline?

No. The 30 days in §5400 is about notifying your employer. The one-year deadline in §5405 is about filing a case with the Workers’ Compensation Appeals Board.

Who signs the notice if the worker died?

A dependent, or someone acting on the dependent’s behalf, according to the text of §5400.

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Sources

• California Labor Code §5400
• California Labor Code §5401
• California Labor Code §5402
• California Labor Code §5403
• California Labor Code §5405
• California Labor Code §5412
• DWC, Information for Injured Workers
• DWC, How to File a Claim

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