Arizona Personal Injury Statute of Limitations: A.R.S. § 12-542 and What Happens If You Miss the Deadline

The Arizona 2-Year Rule — A.R.S. § 12-542

Arizona Revised Statute § 12-542 sets a 2-year statute of limitations for personal injury claims — including car accidents, slip and falls, dog bites, assault, and most other negligence-based claims. The clock starts on the date the injury occurs, or in some circumstances the date you discovered the injury.

This 2-year window is a hard legal deadline. Unlike a simple procedural requirement, the statute of limitations is a substantive bar to recovery. Courts in Maricopa County and throughout Arizona routinely dismiss cases filed even one day late.

Key Deadlines at a Glance

The Discovery Rule — When Does the Clock Start?

Arizona courts apply the "discovery rule" in cases where the injury is not immediately apparent. Under this doctrine, the 2-year clock begins when a reasonable person knew or should have known about the injury and its probable cause — not necessarily the exact date harm occurred.

This most often applies in:

• Medical malpractice — the patient doesn't learn of the negligent act until later symptoms appear
• Toxic exposure — chemical or environmental harm develops over years
• Delayed-onset injuries — a car accident injury that presents days or weeks after the collision

Arizona courts are strict in applying the discovery rule: if a reasonable investigation would have revealed the injury and its cause, the clock starts then — even if you personally didn't investigate. Ignorance alone doesn't extend the deadline.

Government Entities — The 180-Day Notice Requirement

If your injury involved a government vehicle, a dangerous condition on public property, or a government employee's negligence, Arizona law imposes a shorter deadline and a mandatory pre-suit notice requirement. Under A.R.S. § 12-821.01:

• You must file a written Notice of Claim within 180 days of the injury
• The notice must describe the facts, the injury, the damages, and include a dollar amount demanded
• It must be sent to the relevant government entity's statutory agent or highest-ranking officer
• If you miss the 180-day deadline, the lawsuit is completely barred — even if the standard 2-year window hasn't expired

This applies to claims against Maricopa County, the City of Phoenix, the City of Scottsdale, Arizona Department of Transportation, and any other state or local government body. If a ADOT-maintained road caused your accident, the 180-day window controls.

Arizona's Pure Comparative Fault Rule — A.R.S. § 12-2505

Arizona follows pure comparative fault, which is more plaintiff-friendly than the "modified" comparative fault rules used in most states. Under A.R.S. § 12-2505, your damages are reduced proportionally by your percentage of fault — but you are not barred from recovery no matter how high your fault percentage.

In a modified comparative fault state, being more than 50% at fault would bar your claim entirely. In Arizona, you could be 99% at fault and still theoretically recover 1% of damages. This matters in cases where both parties share responsibility.

However, fault allocation is decided by the jury after trial — and insurance adjusters know this. Expect the defendant's insurer to argue your fault percentage is high in order to reduce their payout.

Tolling — When the Clock Pauses

The statute of limitations can be "tolled" (paused) in specific circumstances under Arizona law:

• Minority: If the injured person is under 18, the 2-year clock doesn't start until they turn 18 (meaning suit can be filed up to age 20)
• Mental incapacity: If the plaintiff is legally incompetent at the time of injury, the clock is tolled while the incapacity lasts
• Defendant absence from Arizona: Under A.R.S. § 12-501, time the defendant spends outside Arizona doesn't count toward the limitations period if they're absent to avoid suit
• Fraudulent concealment: If the defendant actively concealed facts that prevented discovery of the cause of action

What Happens If You Miss the Deadline

Missing the statute of limitations deadline is almost always fatal to a claim. The defendant's attorney will file a motion to dismiss, the court will grant it, and you lose your right to recover — regardless of how clear-cut your case is on the merits. There is no "good faith" exception for missing the deadline because you didn't know about it.

In rare cases, courts apply equitable tolling — but Arizona courts apply this doctrine narrowly and reluctantly. "I didn't know about the deadline" is not a basis for equitable tolling. Neither is "I was hoping to settle." Only genuine fraudulent concealment by the defendant or circumstances truly outside the plaintiff's control will move an Arizona court to toll the limitations period by equity.