It's not rocket science... What is Non-Potable Water?

"Non-Engineer" answer: Water that is unsafe to drink.

Explanation: Non-potable water is water that is unsafe to drink due to pollutants or impurities. Non-potable water is often reclaimed waste water that has been cleaned but not purified.

Commentary: Non-potable water is most often used for irrigation or industrial non-consumption processes. Non-potable water can be used for items such as mixing concrete provided the levels of impurities are not too high.