How Far Back Can a Workers’ Comp Audit Go? (And Why “Three Years” Matters)

Most contractors assume that once a policy year is audited and paid, it’s closed for good. Then a re-bill shows up for a job two years back. Carriers can reach further into the past than people expect — here’s how far, and what it means for the records you keep.

The normal cycle: one audit per policy year

Each policy period gets audited shortly after it ends — that’s the routine annual reconciliation. But “audited once” doesn’t always mean “sealed forever.”

Reopening a prior audit

Carriers commonly retain the right to revise an audit for up to about three years after the policy period — though the exact window depends on your state, your policy language, and your contract. An audit can be reopened when:

• New information surfaces — a subcontractor you used turns out to have been uninsured.
• Payroll records are corrected or amended.
• The carrier finds a classification or calculation error in the original audit.

That means a clean audit today isn’t always immune to a re-bill later.

Why this should change how you keep records

If a job can be re-examined years from now, the time to be able to prove a sub had coverage is not the week of the audit — it’s years after the work is done. The contractors who win these later challenges are the ones who can still produce the certificate of insurance showing a workers’ comp line for the exact dates that sub worked.

So keep subcontractor COIs, payroll detail, and classification notes well past the job’s end — at least through the carrier’s revision window. A pre-built audit binder keeps that evidence organized by sub and date, so a re-bill two years out is a five-minute response, not a panic.

It cuts both ways

The lookback isn’t only a threat. If you discover you were overcharged on a past audit — wrongly-added subs, uncapped owner payroll, overtime excess — that prior period can often be revisited in your favor too. Disputing an audit isn’t limited to the most recent one.

The takeaway

Assume any recent policy year can be reopened, and keep your documentation that long. The cheapest insurance against a surprise re-bill is the certificate you already have on file. Check your subs’ coverage and dates →

General information for contractors, not legal advice. Audit revision windows vary by state, policy, and carrier — confirm the limits that apply to you.