There are 3 different categories of water.  Determining which category of water was involved in each situation is especially important in determining the remediation process.

Category 1 Water refers to a source of water that does not pose a substantial threat to humans and is "clean water".  Water that came from a broken pipe would be an example of this, providing the water did not pass over or through a non-clean material.

Category 2 Water refers to a source of water that contains a significant degree of chemicals, biological or physical contaminants which can cause either discomfort or sickness when consumed. Also known as "grey water". This category of water carries micro-organisms and other harmful particles. Some examples of this might be water coming through a basement window or wall, sump pump failures, and water discharge from a dishwasher or washing machine.  Category 2 Water that is not promptly removed from the structure or remains stagnant for 48-72 hours may be reclassified as Category 3 Water.

Category 3 Water is known as "black water" and is grossly unsanitary. This water contains harmful bacteria and fungi and causes severe discomfort or sickness.  This category includes water sources from sewage, seawater, rising water from rivers or streams (likely during flood conditions), and ground surface and standing water. Different removal methods are required for each Category of water. The most important thing in any water damage situation is fast action so it never has a chance to sit and turn into a higher Category.  Again, letting the water sit could cause greater damage and cost more to remediate.