What type of water is described as tap water before treatment?

The term that accurately describes tap water before treatment is "source water." Source water refers to the natural bodies of water, like rivers, lakes, or underground aquifers, from which tap water is drawn and subsequently treated to make it safe for drinking and other uses.

Understanding the terminology is essential for grasping how water resources are managed. Raw water and source water are often used interchangeably, but in this context, source water refers specifically to the original water source before any form of treatment. Feed water, on the other hand, typically refers to water that is used as an input for a specific water treatment process, while pretreatment water suggests a stage in the treatment process rather than the condition of the water itself before any processing.

Therefore, in the context of discussing tap water prior to any treatment, source water is the most appropriate term.