What term describes water that is not safe to drink?

The term that describes water that is not safe to drink is "non potable water." This designation indicates that the water contains contaminants, pathogens, or pollutants that render it unsafe for human consumption. Non potable water may arise from various sources, including untreated water bodies, industrial discharges, or water that has been polluted by human activities.

Other terms, such as "palatable," refer to water that is pleasant to taste and safe for consumption, while "black water" typically describes wastewater that contains human waste and sewage, making it extremely unsafe for drinking. "Raw water" is often used to refer to untreated or minimally treated water directly from natural sources; while it may not be considered safe for drinking, it is not specifically categorized as unsafe like non potable water is. Thus, "non potable water" is the most accurate and comprehensive term for water that should not be consumed.