Two separate deadlines, not one
Suing a government entity in Arizona — the state, a county, a city or town, or another public body — genuinely works differently from suing a private driver or business. Under A.R.S. § 12-821 and its related notice provision, there are actually two separate deadlines to satisfy, and missing either one independently can end the claim.
Step one: a written Notice of Claim within 180 days
Before anything else, a formal, written Notice of Claim must reach the public entity within just 180 days of the date of loss. This notice is a distinct procedural step from filing a lawsuit — it puts the government entity on formal notice of the claim and, in practice, gives it an opportunity to evaluate or resolve the matter before litigation begins. 180 days passes quickly, especially for someone still in the middle of active medical treatment who hasn't yet turned their attention to a formal legal deadline running specifically because the other party happens to be the government.
Step two: the lawsuit itself, within one year
Separately, the underlying lawsuit against the public entity must be filed within one year after the cause of action accrues — exactly half of the ordinary two-year window that applies to a private defendant under A.R.S. § 12-542. Satisfying the 180-day notice requirement does not, on its own, extend or replace this one-year deadline; both requirements exist independently and both have to be met.
Why this two-step structure matters so much
Because these two deadlines are both considerably shorter than Arizona's general two-year rule, and because they work independently of each other, it's entirely possible to lose a valid claim against a government entity by missing the 180-day notice while still believing there's plenty of time left under a rule that doesn't actually apply to this kind of defendant at all. Anyone whose injury might involve a government entity in any way — a public road, a government vehicle, a public building, a government employee acting within the scope of their duties — should treat that 180-day window as the operative deadline from day one, not the familiar two-year figure.
The rule this interacts with
See our Arizona statute of limitations calculator for how these two shortened government deadlines compare side by side to the ordinary two-year rule for a private defendant, worked out for a specific injury date.