Water

Drinkable Water
Drinkable water should be fresh, running, clear of debris or contaminants, and upstream of water used by a different process.

To create drinkable water from undrinkable water, different methods of making it usable depend on the water's possible contaminants.

Turbidity
(thick or opaque with or as if with roiled sediment )

Greywater
Water previously used by another household process such as sink, laundry, or bathing is classified as Greywater. (NOTE* toilet water is NOT Greywater)

While Greywater has already been used by another process, it is not uncleanable or unusable for another.

http://greywater.net/