Not every flood carries the same risk. Water from a split supply line, water from an overflowing washing machine and water that has come up through a floor drain from the sewer can look almost identical on a basement floor, yet each is handled very differently. To keep those decisions consistent, the restoration trade relies on a three-level system set out in the ANSI/IICRC S500 standard, published by the Institute of Inspection, Cleaning and Restoration Certification.
Category 1 is usually called clean water. It comes from a sanitary source and poses no substantial risk if someone touches it or breathes near it. A broken supply line, a leaking faucet connection or a bathtub that overflowed without soap or other additives are typical examples.
Category 2, or grey water, carries enough contamination to cause discomfort or illness if people are exposed to it. Discharge from a dishwasher or washing machine, an overflowing toilet bowl containing urine but no feces, groundwater seeping through a foundation under hydrostatic pressure, and water from a broken aquarium all belong here.
Category 3, black water, is grossly contaminated and may contain bacteria, viruses, fungi or chemicals. Sewage backups, toilet overflows that originate beyond the trap, and floodwater rising from rivers, streams or overland flow fall into this group. Anything that sat in that water is treated as contaminated as well.
A point that often gets missed is that the category can change. Clean water does not stay clean once it has soaked through carpet, picked up dirt from a subfloor or sat in a warm basement for a couple of days. Time, temperature and the materials the water touches can turn a Category 1 loss into Category 2, and a Category 2 loss into Category 3. That is one reason a supply-line leak found within the hour is a much simpler job than the same leak found after a long weekend away.
The category shapes most of what follows. Clean water caught early may allow carpet to be dried in place and drywall to be dried rather than cut out. Grey water generally means the carpet pad is replaced and more cleaning and antimicrobial treatment is involved. Black water typically means porous materials such as carpet, pad, insulation and the lower part of the drywall are removed and discarded, workers wear protective equipment, and the affected area may be sealed off from the rest of the house.
The standard also uses a separate scale of classes to describe how much water is present and how difficult the space will be to dry, ranging from a small area of low-absorbency material to deeply saturated hardwood, plaster or concrete. Category describes how dirty the water is; class describes how wet the structure is. The two are assessed independently.
For homeowners, the practical value of the system is knowing when to step back. Mopping up a small leak from a sink supply line and running a fan is reasonable. Sewage on a basement floor is another matter entirely: contact should be avoided, children and pets kept away, and cleanup left to people with the right equipment and protection.
In Strathcona County, where many basements are finished living space and a good number of acreages run on septic systems, backups are a familiar risk. When one does happen, a company offering water damage restoration in Sherwood Park should be able to say which category it assigned to the loss and how that affects what stays and what goes.
Asking is not about second-guessing the crew. The category sets the scope of the work, and understanding it makes the estimate, the tear-out and any conversation with an insurer easier to follow.