Raw water

Raw water is water in its natural state, exactly as it arrives from the environment before any treatment has occurred. It may be drawn from a surface source, such as a river, lake, or reservoir, or from a groundwater source through wells. Whatever its origin, raw water carries whatever the environment put into it: suspended particles, dissolved minerals, organic matter, and microorganisms. It is the starting material of the entire drinking water process.

The character of raw water varies enormously from one source to another and even from one day to the next at the same source. Storms can stir up sediment, seasons change temperature and biological activity, and land use in the watershed influences what washes in. Operators pay close attention to raw water quality because every downstream treatment decision depends on what is coming in the front door of the plant.

On certification exams and in daily plant vocabulary, raw water is contrasted with finished or potable water, the product leaving the plant. A useful way to think about a water treatment career is that the operator's whole job is managing the journey from raw to finished: understanding the source, applying the right processes, and verifying that the transformation is complete before the water reaches the public.

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