Afterloss The first hour
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Category 3 — Grossly contaminated water

Professional requiredThis page explains the work. It does not tell you how to do it, because doing it without training and equipment is unsafe.

Water category: Category 3 — Grossly contaminated water

Porous materials that contacted Category 3 water are generally removed and discarded. Drying is not a substitute for removal, and this is the single most expensive determination in a water loss.

Grossly contaminated and can contain pathogenic, toxigenic or other harmful agents — sewage, a toilet backup beyond the trap, rising water from rivers or streams, wind-driven rain carrying ground contaminants. Porous materials that contacted Category 3 water are generally removed and discarded. Drying is not a substitute for removal, and this is the single most expensive determination in a water loss.

Where it comes from

Grossly contaminated and can contain pathogenic, toxigenic or other harmful agents — sewage, a toilet backup beyond the trap, rising water from rivers or streams, wind-driven rain carrying ground contaminants.

What it means for the work

Porous materials that contacted Category 3 water are generally removed and discarded. Drying is not a substitute for removal, and this is the single most expensive determination in a water loss.

How it changes with time

Category 3 is the end of the scale. It does not improve with time.

This is the part that explains the bill. The same loss, addressed in six hours or discovered in six days, can be two different scopes.

Why this needs a professional

This page explains what Category 3 water is and what follows from it. It contains no cleaning or removal procedure, and that omission is deliberate: porous material that contacted it is generally removed rather than dried, and that determination is not made by looking.

What comes next

Anything left wet becomes a mold question once EPA's 24 to 48 hour drying window has passed. See mold and mold sublimits.

Sources

Every source cited on this page

  1. T2ANSI/IICRC S500 — IICRC (accessed 2026-08-22)
  2. T1A Brief Guide to Mold, Moisture and Your Home — US EPA (accessed 2026-08-22)
  3. T1About Mold and Health — CDC (accessed 2026-08-22)
Written by: PLACEHOLDER — Restoration ReviewerReviewed by: PLACEHOLDER — Claims ReviewerSafety reviewed by: PLACEHOLDER — Restoration ReviewerLast reviewed:

Guidance that does not name a water category, a smoke type, or the peril and whether the water was internal or external is not specific enough to act on. This page names them.