What label is required on all gray water piping?

• A. Non-Potable
• B. Reclaimed Water
• C. Danger-Unsafe Water
• D. Bad Water

Answer: (C)

Clear labeling on piping that carries non-potable water is about signaling hazard so people don’t confuse it with drinking water. Gray water isn’t safe to drink, so the marking should immediately convey risk. “Danger – Unsafe Water” does that most forcefully, warning anyone who handles or inspects the system that the contents are hazardous and not for consumption.

Other labels are less effective in conveying immediate danger: “Non-Potable” tells you it’s not drinkable but doesn’t scream danger; “Reclaimed Water” suggests it’s treated for reuse and could be misinterpreted as potable under some circumstances; “Bad Water” is vague and not a standard warning. The strongest, clearest caution is the explicit danger notice. Always follow local codes for exact wording, but the principle is to make the hazard immediately obvious.