What is the difference between cat 1 and cat 2?

The difference between cat 1 and cat 2 depends on context where those categories are used. In water damage restoration, CAT 1 and CAT 2 refer to categories of water contamination, CAT 1 is clean water from a sanitary source like a broken supply line that does not pose substantial health risk, while CAT 2 is significantly contaminated gray water from sources like dishwasher discharge, washing machine overflow, or toilet overflow with urine that may cause illness if ingested and requires more protective measures. CAT 3 would be black water that is grossly contaminated. In other contexts, CAT 1 and CAT 2 might refer to different categories of something else, such as hurricane categories, medical triage, or cable types where CAT 5 and CAT 6 refer to ethernet cable standards, or in automotive repair CAT 1 and CAT 2 might refer to parts categories. In pest control, categories might refer to pesticide toxicity. To give a precise answer, you need to specify the industry, but the most common use of CAT 1 versus CAT 2 is in water damage classification where the difference is level of contamination and health risk and required remediation procedures.