# Water damage: categories, classes and cost Water damage is classified by category 1, 2 or 3 and by class 1 to 4. The category decides what can be dried and what must be removed, and it degrades with > Source: https://servpronorhfremont.com/water/ > Last reviewed: 2026-08-21 --- - Home - Water damage # Water damage Dry is a measurement, not a feeling. - Water - 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 damage is graded by category — 1 clean, 2 significantly contaminated, 3 grossly contaminated — and the category decides whether porous materials are dried in place or removed. Category degrades with time and contact, which is why the same leak costs very different amounts depending on how long it sat. ## The three categories # Link to this section The category describes what is in the water, not how much of it there is. It is the first thing anyone should establish, and guidance that does not name it is not specific enough to act on. Category What it is What it usually means Category 1 Water from a sanitary source — supply line, water heater feed Most materials can be dried in place if drying starts quickly Category 2 Significantly contaminated — appliance discharge, toilet overflow with urine only Porous materials frequently come out rather than being dried Category 3 Grossly contaminated — sewage, rising external water, wind-driven rain carrying ground contaminants Porous materials that contacted it are generally removed and discarded ## The fact that explains the bill # Link to this section Category degrades with time. Category 1 water that sits in building materials picks up contamination and stops being Category 1. Category 2 degrades to Category 3. This is the mechanism behind most of the cost variance in water losses, and it is why the answer to “how much will this cost” genuinely depends on when the drying started. The same burst pipe, dried in six hours or discovered in six days, is two different scopes. ## Classes 1 to 4 # Link to this section Where category describes contamination, class describes how much water the materials absorbed and therefore how hard the structure is to dry — from a small area with minimal absorption through to materials like hardwood, plaster and concrete that release water very slowly. ## “Dry” means a measurement # Link to this section A surface can feel dry while the material behind it is saturated. Drying is verified with moisture meters and hygrometers against a documented goal, recorded daily. If equipment is running in your home and nobody is producing a daily monitoring log with readings, there is no evidence the drying is working — and no evidence for your claim either. ## Why this needs a professional Category 2 and Category 3 water, anything standing for roughly 24 to 48 hours, anything inside a wall assembly or under a floor, and anything involving an electrical panel or wet wiring all require training and equipment a homeowner does not have. This page explains the framework; it contains no procedure for any of those, and that omission is deliberate. ## What comes next Wet porous material that is not dried to a documented moisture goal is a mold problem within roughly 24 to 48 hours. See mold , and because coverage for it is capped, mold sublimits . ## Related questions - The first hour after a water loss - After a house fire: suppression water - Mold after water damage - Why flood is excluded - Mold coverage is capped - What to photograph and log ## Sources Every source cited on this page - T1 Mold, Moisture and Your Home — EPA (accessed 2026-08-21) - T2 ANSI/IICRC S500 / S700 — IICRC (accessed 2026-08-21) - T1 Carbon Monoxide Poisoning — CDC (accessed 2026-08-21) Written by: PLACEHOLDER — Restoration Reviewer Reviewed by: PLACEHOLDER — Claims Reviewer Safety reviewed by: PLACEHOLDER — Restoration Reviewer Last reviewed: 2026-08-21 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.