gray water

noun

dirty water from sinks, showers, bathtubs, washing machines, and the like, that can be recycled, as for use in flushing toilets.

Origin of gray water

First recorded in 1975–80

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

graywater in Science

graywater

[grā′wô′tər]

Wastewater from baths, bathroom sinks, and washing machines that does not contain body or food wastes. Graywater can be recycled especially for use in gardening or for flushing toilets. Compare blackwater.