Clean, Grey or Black Water
What Does that mean to your Property

In Flood Restoration, we define water in 3 different categories.  We use the terms Cat 1, Cat 2 and Cat 3.  You might also hear the categories described as Clean, Grey and Black.

Cat 1 - Clean Water

Clean water, also known as Cat 1 water, is water that has come directly from a fresh water source and is less than 48 hours since the event began.  Typically, clean water losses are burst pipes, leaking refrigerator cold water inlets, overflowing basins and baths and leaking plumbing.  

In cat 1 losses, almost everything is salvageable.  Carpets can be cleaned, furniture can be cleaned and cabinets can be dried.

 Cat 2 - Grey Water

Grey water, also known as Cat 2 water, is water that has come from a slightly contaminated source.  Examples are washing machine overflows and fish tanks.  We also consider freshwater that has been unattended to after 48 hours as being grey water.  If fresh water has wet a carpet that may have pet urine on it or under it, we would also consider this to be grey water.

With Grey Water, we make a judgement call on whether an item is salvageable.  Where there may be a dispute or health compromised occupants use the building, we will take swab samples for analysis with our mycometer.  Grey Water can become Black Water very quickly.

Cat 3 - Black Water

Black water, also known as Cat 3 water, is anything that has come up past an S-Bend, regardless of smell or the presence of sewage.  

Any water that has entered a property as a result of flooding is also considered to be Black Water.

With Black Water, virtually nothing is salvageable.  If an item is porous or semi porous, including building elements (skirting boards, plaster, etc) they should be removed.

Before damaging a building we will often conduct a dry steam clean and disinfection and then test the surface with our mycometer to determine if bacterial load has been reduced to safe levels.

Special Circumstances

With regard to storm water entering via a roof, the IICRC S500 (2015) standard allows the technician discretion to determine whether the category of water is cat 2 or cat 3.  Given the cost and health implications of this decision, we use our mycometer to determine the bacterial load to make a determine on the category of water.

With regard to water originating from a toilet bowl, but not from below the trap, the IICRC S500 (2015) standard classes this as grey water.  Given the cost and health implications of this decision, we use our mycometer to determine the bacterial load to make a determine on the category of water.