gryoung et al,
Here is a definition of Gray Water excerpted from this site:
http://www.umassgreeninfo.org/fact_s...r_gardens.html
First, what is gray water?
Gray water is all the
non-toilet wastewater produced in the average household including the water from bathtubs, showers, sinks, washing machines, and dishwashers. Although gray water does not need extensive chemical or biological treatment before it can be used in the garden as irrigation water, it still must be used carefully because it usually contains grease, hair, detergent, cosmetics, dead skin, food particles and small amounts of fecal matter.
Basically what comes out of the faucet is potable (drinkable) water, what comes out of the sprinklers is non-potable water. Non potable can be filtered and purified to become potable water as well as gray water; obviously turning gray water into potable water is rather involved and costly.
Black water is what we flush down the toilet and into the sewer.