The eco-focused people who are trying to “save” their plants by pouring dish and bath water over them are actually committing a crime. North Carolina state law prohibits pouring anything headed for the drain onto outside, even if it is clean, leftover water from dinner glasses.
Dana Domrongchai of Indian Trail has managed to save 20 gal of water per week this way. She told The Charlotte Observer that she doesn’t “see the problem. It's my water on my plants, and nobody else is affected. I'd never have considered it contaminated."
Barbara Hartley Grimes, program coordinator at the state Division of Environmental Health, disagrees, saying that “gray water”—water discharged from bathtubs, sinks, showers and washing machines—is wastewater, as defined by state plumbing codes. This water can contain bacteria, fungi, chemicals and other contaminants that can make people sick, she says.
As she told the Observer "What you're talking about is throwing out slop water. I don't want people thinking they can get away with it if nobody sees it. It is a public health hazard."
Of course, wastewater dumping is a very difficult crime to prove, as it requires soil samples to be taken before any legislative action is taken. Usually, even when such an action is documented, the Division is not interested in prosecuting—only educating.
The only exceptions to the rule is water that is used when waiting for the shower to cool or warm—as long as it has not touched you—or water from the kitchen sink that hasn’t made contact with food and other waste.