Restoration professionals sort water into three categories described in the ANSI/IICRC S500 standard. The category tells a crew how to protect itself, which materials to remove and how to clean. This article explains each in plain language and shows how a category can change over time.
You can ask any company whether its crews work to S500, and whether it has classified your water.
Category 1: clean water
Category 1 water comes from a sanitary source such as a supply line, a faucet or a tub overflow. It poses little risk at the moment it is released. Examples are a burst supply pipe, a water heater tank failure and rainwater from a clean roof.
Materials exposed to Category 1 water can often be dried in place if the response is quick. Delay turns it into Category 2 as bacteria and debris accumulate.
Category 2: significantly contaminated
Category 2, sometimes called gray water, contains contaminants that could cause discomfort if people touch it or drink it. Examples are discharge from a washing machine or dishwasher, overflow from a toilet with urine only and water from an aquarium.
Porous materials such as carpet pad are often removed, and carpet may be saved depending on the situation. Cleaning and sanitizing are part of the work.
Category 3: grossly contaminated
Category 3 water contains pathogens, chemicals or other harmful matter. Sewage, flood water from rivers or streams and water from a toilet with feces fit here. Standing water that has sat long enough to grow organisms can also reach Category 3.
Porous materials are generally removed and discarded. Hard surfaces are cleaned and sanitized. The work uses protective gear and containment. See sewage backup cleanup and flood damage cleanup.
The three categories side by side
A comparison helps.
| Category | Typical source | Typical response |
|---|---|---|
| 1 clean | Supply line, tank, tub overflow | Extract and dry in place when caught fast |
| 2 gray | Washer or dishwasher discharge | Remove pad, clean, sanitize, dry |
| 3 black | Sewage, flood water | Remove porous materials, clean, sanitize, dry |
A category is a starting point. The crew re-checks it as conditions change.
How a category can change
Clean water that sits in a carpet for a few days can become Category 2. Gray water left in a closed wall can become Category 3. Temperature, time and the materials involved all push the category up.
That is why speed matters, and why a crew asks how long the water has been present. The category is not fixed at the moment of the loss. It is a judgment about conditions now.
What the category means for your insurer and bill
Higher categories usually mean more labor, more disposal and more protective measures. They can also change the answer on coverage. Sewer backup, for example, is often covered only with an endorsement, as noted by the Massachusetts Division of Insurance.
Ask your insurer how it treats each category under your policy. A drying log that records the category and the reasons for it makes the discussion easier.
Safe steps for each category
For Category 1, stop the source and begin extraction. For Category 2, wear gloves and boots, keep children and pets away and call a professional. For Category 3, stay out and call. Do not try to clean it with towels.
If you are not sure which category applies, assume the higher one until a professional says otherwise. The extra caution costs little.
Categories in everyday examples
A kitchen supply line that splits under the sink is Category 1 if it is caught within hours. The same water left in cabinet bases for three days is no longer clean. A washing machine overflow that carried detergent and lint is Category 2. Water that came up a floor drain after a heavy storm is Category 3.
Thinking in examples helps you ask the right question on the phone. Tell the dispatcher where the water came from and how long it has been there. Those two facts give a crew the starting category.
Protective gear and containment by category
For Category 1, a crew may need only gloves and boots. For Category 2, gloves, boots and eye protection are standard, and the area is kept closed to other occupants. For Category 3, the crew wears protective suits, respirators and gloves, seals the area with plastic and uses air filtration.
Containment keeps contamination from moving into clean rooms. If you see a crew setting up plastic and a negative air machine, that is why. The aim is to keep what they disturb inside the work area.
What homeowners can safely do by category
With Category 1, you can stop the source, move belongings and use a wet vacuum on small spills. With Category 2, keep children and pets away, wear protective gear and leave porous materials for a professional to assess. With Category 3, do not touch it. Leave the area and call.
If you are unsure, treat the water as the higher category. The difference in cost and effort is small compared with the risk of cleaning contaminated material the wrong way.
Documentation by category
Record the source, the time the water began, the time it was stopped and who first saw it. Record what the water touched. Photograph the water before cleanup. A crew should note the category and the reason in the drying log.
If a category is changed during the job, for example from 1 to 2 because of delay, the log should show when and why. That clear reasoning supports the work and any claim.
Questions homeowners ask about categories
People often ask whether Category 1 water is safe to drink or touch. It is clean when released, but that does not make it safe once it has picked up dust or sat in building materials. People also ask whether they can keep a rug that got Category 2 water. It depends on the rug and the cleaning method, and a professional can advise.
Key points to remember
Category 1 is clean, Category 2 is significantly contaminated and Category 3 is grossly contaminated. The source, the time and the materials set the category, and the category sets the cleanup. Contaminated water means porous materials usually go. When unsure, assume the higher category until a professional says otherwise. Ask any company whether it follows ANSI/IICRC S500, and ask to see the category noted in the drying log.
A Norton note on sewer and septic
Not every Norton home connects to a public sewer, and some use septic systems. Ask the Norton Board of Health or the building department which applies to your address, because a septic overflow and a sewer backup involve different repair contractors. The cleanup category for both is typically Category 3.
Related pages and nearby towns
The first stage is described under water extraction. The same standards apply for homeowners in South Easton and Mansfield.
Common questions
Category 1 at the start. It can degrade if it sits.
Often yes, depending on the source and what the machine carried.
Surface flood water is generally treated as Category 3.
The restoration professional classifies it and may change it as conditions change.
Generally not. Porous materials are removed.
References for this article
Facts here come from the EPA mold and moisture pages, the Massachusetts Division of Insurance and the published ANSI/IICRC S500 and S520 standards. Your own policy and your town decide the details that apply to you.