# Category 3 — Grossly contaminated water Grossly contaminated and can contain pathogenic, toxigenic or other harmful agents — sewage, a toilet backup beyond the trap, rising water from rivers or > Source: https://servpronorhfremont.com/water/categories/category-3-water/ > Last reviewed: 2026-08-22 --- Read this before anything else ## Biohazard exposure Sewage, blood, or other potentially infectious material should not be cleaned without training and protective equipment. Exposure to bloodborne pathogens is an occupational hazard governed by a federal standard for a reason. - Home - Water categories and what must be removed - Water categories - Category 3 # Category 3 — Grossly contaminated water - Water - Biohazard - Mold Professional required This 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 # Link to this section 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 # Link to this section 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 # Link to this section 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 . ## Related questions - The first hour after any loss - Water categories and what must be removed - Mold and the drying window - What your policy covers - What to photograph and log ## Sources Every source cited on this page - T2 ANSI/IICRC S500 — IICRC (accessed 2026-08-22) - T1 A Brief Guide to Mold, Moisture and Your Home — US EPA (accessed 2026-08-22) - T1 About Mold and Health — CDC (accessed 2026-08-22) Written by: PLACEHOLDER — Restoration Reviewer Reviewed by: PLACEHOLDER — Claims Reviewer Safety reviewed by: PLACEHOLDER — Restoration Reviewer Last reviewed: 2026-08-22 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.