When Does a Category 1 Water Loss Become Class 2 or 3?

water loss in kitchen

What are the categories of a water loss? Under what circumstances should a water damage loss be classified as Category 3 (IICRC S500) and therefore treated as a “grossly contaminated environment?”  The answer could greatly increase demolition and decontamination required.

In a Category 1 water loss, the alternative on the other end of the contamination scale, is only an issue when materials are wet.  A Category 1 environment “does not pose substantial risk from dermal, ingestion, or inhalation exposure.” With Category 1, restorative drying, in which removal of the water is the primary response, is often fully effective if properly implemented at returning the building to pre-loss conditions.

Note: “Category 2” refers to environments that are not grossly contaminated as for Category 3, but that do “contain(s) significant contamination and has the potential to cause discomfort or sickness if contacted or consumed by humans.”  The appropriate response for a Class 2 water loss is on a sliding scale, depending on the severity of the contamination present.

Below see the definitions for Category of Water as found in ANSI/IICRC S500-2015 Standard and Reference Guide for Professional Water Damage Restoration.  This document is available from the IICRC Webstore.

Defining Water Loss Categories 1, 2 & 3

Category of Water (S500-2015, pages 11 – 12): The categories of water, as defined by this article, refer to the range of contamination in water, considering both its originating source and quality after it contacts materials present on the job site. Time and temperature can affect or retard the amplification of contaminants, thereby affecting its category. Restorers should consider potential contamination, defined as the presence of undesired substances; the identity, location and quantity of which are not reflective of a normal indoor environment; and can produce adverse health effects, cause damage to structure and contents or adversely affect the operation or function of building systems.

Category 1 Water:  Category 1 water originates from a sanitary water source and does not pose substantial risk from dermal, ingestion, or inhalation exposure. Examples of Category 1 water sources can include, but are not limited to: broken water supply lines; tub or sink overflows with no contaminants; appliance malfunctions involving water-supply lines; melting ice or snow; falling rainwater; broken toilet tanks, and toilet bowls that do not contain contaminants or additives.

Category 1 water can deteriorate to Category 2 or 3. Category 1 water that flows into an uncontaminated building does not constitute an immediate change in the category. However, Category 1 water that flows into a contaminated building can constitute an immediate change in the category. Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water. Odors can indicate that Category 1 water has deteriorated.

Category 2 Water: Category 2 water contains significant contamination and has the potential to cause discomfort or sickness if contacted or consumed by humans. Category 2 water can contain potentially unsafe levels of microorganisms or nutrients for microorganisms, as well as other organic or inorganic matter (chemical or biological). Examples of category 2 water can include, but are not limited to: discharge from dishwashers or washing machines; overflows from washing machines; overflows from toilet bowls on the room side of the trap with some urine but no feces; seepage due to hydrostatic pressure; broken aquariums and punctured water beds.

Category 2 water can deteriorate to Category 3. Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water.

Category 3 Water:  Category 3 water is grossly contaminated and can contain pathogenic, toxigenic or other harmful agents and can cause significant adverse reactions to humans if contacted or consumed. Examples of Category 3 water can include, but are not limited to: sewage; wasteline backflows that originate from beyond any trap regardless of visible content or color; all forms of flooding from seawater; rising water from rivers or streams; and other contaminated water entering or affecting the indoor environment, such as wind-driven rain from hurricanes, tropical storms, or other weather-related events. Category 3 water can carry trace levels of regulated or hazardous materials (e.g., pesticides, or toxic organic substances).

Regulated, hazardous materials, and mold: if a regulated or hazardous material is part of a water damage restoration project, then a specialized expert may be necessary to assist in damage assessment. Restorers shall comply with applicable federal, state, provincial and local laws and regulations. Regulated materials posing potential or recognized health risks can include, but are not limited to: arsenic, mercury, lead, asbestos, polychlorinated biphenyls (PCBs), pesticides, fuels, solvents, caustic chemicals and radiological residues. For situations involving visible or suspected mold, refer to the current version of ANSI/IICRC S520 Standard and Reference Guide for Professional Mold Remediation. Qualified persons shall abate regulated materials, or should remediate mold prior to restorative drying.

Understanding Categories of Water Loss

In this discussion, quotes from S500 are in italics, while IET commentary is in regular text.

In the definition of Category 1, note that “Category 1 water can deteriorate to Category 2 or 3.”  However, this is immediately followed by a definition of the conditions under which such a deterioration may be considered to have occurred.

  • “Category 1 water that flows into an uncontaminated building does not constitute an immediate change in the category.” Hence, a “normal” home or office that gets wet is by definition Category 1, unless and until some event or process changes the Category.
  • “However, Category 1 water that flows into a contaminated building can constitute an immediate change in the category.” This is the inverse of the preceding statement.  If a building already contains materials that pose a significant health risk to people, adding water likely spreads this existing contamination and increases the health risk, meaning the environment is properly classified as Category 3.  (Or perhaps 2 if the degree of contamination is less severe.)

S500 then defines the conditions under which an originally Category 1 water damage loss might be considered to have changed its category of water to 2 or 3:  “Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water. Odors can indicate that Category 1 water has deteriorated.”

Normally, a Category 1 water damage loss in which proper restorative drying begins quickly would not be considered to become Category 2 or 3, unless and until it is shown that microbial contamination, usually mold growth, is present that requires remediation/decontamination.  This can happen, even in a building being professionally dried, for many reasons:  weather conditions, incompetence of the restorer, inadequate or improperly deployed equipment, interference with the work needed by building owners, etc.

The presence of contamination turning an originally Category 1 loss into a higher Category should be demonstrated, ir possible, not just assumed.  Even if contamination is demonstrated, so that the environment is no longer appropriately classified as Category 1, it may be appropriately reclassified as anywhere along the Category 2 spectrum, if the “gross contamination” posing significant health risks indicative of Category 3 is not present.

In the definition for Category 3 it is recognized that significant mold growth (like the presence of other health risks) can create a hazardous environment qualifying as Category 3.  However, at the point when the presence of significant such risks is discovered, the project moves beyond the purview of S500.  “Regulated, hazardous materials, and mold: if a regulated or hazardous material is part of a water damage restoration project, then a specialized expert may be necessary to assist in damage assessment.”  Mold is of course not regulated in many jurisdictions, but it can be considered hazardous.

Classifying Water vs Mold Damage Restoration

Once the presence of mold is discovered, the issue becomes primarily one of mold remediation, not water damage restoration, and the procedures for dealing with a Category 3 water loss are no longer specifically relevant. “For situations involving visible or suspected mold, refer to the current version of ANSI/IICRC S520 Standard and Reference Guide for Professional Mold Remediation. Qualified persons … should remediate mold prior to restorative drying.” That is to say, a wet building where significant mold growth has occurred becomes primarily a mold remediation project.  The fact that some materials may be wet becomes very much a secondary issue.  Drying those materials also becomes of secondary importance, since those materials will mostly be removed during proper mold remediation.

In any environment contaminated with mold, whether it is or has been wet or not, the procedures outlined in IICRC S520 should be followed.  These can be abbreviated as follows:

  1. Investigation by a qualified Indoor Environmental Professional (IEP) to document presence of contamination and develop a Protocol for remediating it.
  2. Remediation by a qualified and, if relevant, licensed professional:
    1. Removal of porous or non-restorable materials.
    2. Aggressive cleaning of semi-porous, restorable materials such as wood framing.
    3. Detailed cleaning of all affected areas to a “normal fungal ecology,” or pre-loss conditions.
  3. Documentation of successful completion of remediation, best accomplished by a Post-Remediation Verification inspection and report by an IEP.
  4. Reconstruction as needed.

The 2015 edition of S500 makes very clear what has been only implied in earlier versions.  In a contaminated Category 3 environment, the contamination is the primary issue.  That materials are wet is of secondary importance.  Normally, a contaminated environment should be decontaminated first and only then aggressively dried, although of course some drying can be underway throughout the remediation/restoration process.

Please contact IET if you have questions about how these principles might be properly applied to a given project.

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