Ok, here's the scene: The midwest has been in a drought for several years. Last year there was a crop failure due to a lack of water. In the cities, lawns are hurting, backyard gardens are pitiful. Water restrictions are in effect (although some ignore them - you can recognize these selfish people by their lush lawns).
On a certain city's Facebook page (isn't everyone on Facebook now??) a discussion of how to save water arises. One poster mentions using the rinse water from doing dishes to wash the car windows. Almost immediately, the city worker who is in charge of their Facebook page answers that using gray water is illegal.
There was no answer from the original poster and the discussion tapered off into nothing.
Believe it or not, that actually happened. In some areas, no matter how dear and scarce water is, it's illegal to rinse a dish, then take the water you caught from it and use it for anything, not even washing a car window or mopping the floor.
If you put a container under the faucet when you rinse your hands, then use that to water your houseplants, you're breaking the law.
For all of you law abiding citizens out there, be sure to check local ordinances before using the great ideas in this article:
Recycling Gray Water
If you can use them, do. It doesn't matter if you're in a drought area or not, wasting water costs both in terms of money and the environment.