California Workers' Compensation Filing Deadlines — A Complete Guide

What are the actual deadlines in a California workers' comp case?

Employers must be notified of a work injury within thirty days; the formal workers' comp claim must be filed within one year of the injury date.

The deadlines below are listed in the order they typically come up, from the moment of injury through the final appeal. Each one matters, each one has a fix when missed for good cause, but each one is easier to hit on time than to litigate around later.

30 days, notice to employer under §5400

A California worker must report the injury to the employer within 30 days under California Labor Code §5400. The report should be in writing, a text, an email, or a signed note. A verbal report is legally valid but easy for the employer to deny later. For a cumulative-trauma injury under California Labor Code §3208.1, the 30-day clock runs from the date the worker knew or should have known the condition was work-related. A missed 30-day deadline can sometimes be excused for good cause, but it is the most common insurer defense to a late-reported injury.

1 working day, DWC-1 claim form under §5401

Once the employer learns about the injury, the employer must provide a DWC-1 claim form within one working day under California Labor Code §5401. This is the employer's obligation, not the worker's, but the worker should ask for the form. If the employer does not provide it, the worker can download the DWC-1 directly from the California Division of Workers' Compensation at dir.ca.gov.

1 day, $10,000 in initial treatment under §5402(c)

California Labor Code §5402(c) requires the insurer to authorize up to $10,000 in medical treatment within one day of the completed DWC-1, even during the 90-day decision window, even if the claim is later denied. A worker who needs urgent care should not wait on paperwork.

90 days, insurer decision under §5402(b)

Once the completed DWC-1 reaches the insurer, the insurer has 90 days to accept or deny the claim under California Labor Code §5402(b). If the insurer does not decide within 90 days, the injury is presumed compensable, meaning the law treats the claim as accepted by default. A late denial may not be a valid denial at all.

1 year, statute of limitations under §5405

A California worker generally has one year from the date of injury to file a workers' compensation claim under California Labor Code §5405. For a specific injury, the clock runs from the date of the incident. For a cumulative-trauma injury under California Labor Code §3208.1, the clock runs from the date the worker knew or should have known the condition was work-related and disabling.

5 years, reopen for new and further disability under §5410

After a Stipulated Award, the worker can petition to reopen the claim for new and further disability within five years of the date of injury under California Labor Code §5410. After a Compromise and Release, the right to reopen is generally extinguished. The five-year reopen right is one of the most valuable features of a Stipulated Award.

10 days, QME panel strike under §4062.2

Each side has 10 days from receipt of the QME panel to strike one name under California Labor Code §4062.2. Missing the 10-day window without good cause forfeits the right to influence the panel. The remaining QME (or AME, in represented cases) conducts the evaluation.

30 days, Independent Medical Review under §4610.5

If the insurer's Utilization Review under California Labor Code §4610 denies a treatment request, the worker has 30 days to appeal through Independent Medical Review under California Labor Code §4610.5. An independent physician then reviews the medical record and either upholds or overturns the denial. The 30-day IMR clock is short and unforgiving, missing it usually means accepting the UR denial.

25 days mailed / 20 days electronic, Petition for Reconsideration under §5903

After a workers' compensation judge issues a Findings and Award, the deadline to file a Petition for Reconsideration with the WCAB is 25 days from service by mail (20 statutory days plus 5 added by the WCAB rules of practice when service is by mail) or 20 days from electronic service via EAMS, under California Labor Code §5903. The petition must state one of the six statutory grounds for reconsideration. This deadline is hard, the WCAB has limited ability to extend it.

45 days, Writ of Review under §5950

If the WCAB denies reconsideration, the worker has 45 days from the WCAB's decision on reconsideration to file a Writ of Review with the California Court of Appeal under California Labor Code §5950. The Writ is the last appellate step before the case becomes final.

Which of these deadlines actually catches workers most often?

The retaliation petition has a one-year deadline from the retaliatory act; the IMR appeal has a strict thirty-day deadline from the UR denial letter.

Three deadlines cause most of the trouble in California claims. First, the 30-day notice to employer under California Labor Code §5400, workers who push through pain for weeks before reporting often face a §5400 defense. Second, the 30-day IMR appeal under California Labor Code §4610.5, workers who get a UR denial letter and do not understand what it means often miss the IMR window and end up paying for treatment out of pocket. Third, the 25-day Petition for Reconsideration under California Labor Code §5903, workers who try to handle an adverse Findings and Award without an attorney often miss the short reconsideration deadline.

Related on yazdchilaw.com: California workers' compensation lawyer pillar · what to do if you can't go back to work after a workers' comp injury · what happens if the workers' comp judge mishears your testimony · can you keep workers' comp if you move out of state · California Labor Code §3600 explained.