purple water
n.— «An alternative to using gray water is treating it with a home sanitizer system to create what’s known as “purple water.” While it’s not safe enough to drink, purple water is considered safe enough for use on lawns, golf courses and irrigation in other states.» —“Scientist sees gray water risk” by Benjamin Price Athens Banner-Herald (Georgia) Nov. 25, 2007. (source: Double-Tongued Dictionary)
Further reading
If you alternate alcoholic beverages with glasses of water over the course of an evening, you’re said to be zebra striping. This bit of slang was inspired by how the animal’s alternating black-and-white markings are like the contrast between the...
You might be surprised to learn that a “hoosier” isn’t necessarily from Indiana. Around the St. Louis, Missouri, area, the term hoosier has a whole other meaning. And: Scotland is the home of the Golden Spurtle world championship, but what exactly...
FWIW, purple is the color used to identify recycled water pipe. while i know purple water shouldn’t(?) kill me, on a hot summer day i will check to see if the lawn water is spraying out of a purple sprinkler head before driving in.