What term defines fresh or sea water that has not been previously treated?

The term that defines fresh or sea water that has not been previously treated is "raw water." This is water sourced directly from the environment, such as rivers, lakes, or groundwater, without undergoing any purification processes. Raw water can contain various natural contaminants such as sediments, pathogens, and organic matter, making it unsuitable for direct human consumption or use without treatment.

Understanding the distinction between raw water and the other options is essential for grasping water quality management. Black water refers specifically to wastewater from toilets, which contains human waste and is highly contaminated. Contaminated water encompasses any water that has been polluted by harmful substances and poses health risks, while palatable water refers to water that is safe and pleasant for consumption—usually treated to remove impurities. Thus, raw water is the correct term for water in its unprocessed state.