Water reuse can be indirect or direct potable reuse. Which statement correctly differentiates them?

• A. Water reuse refers to treating wastewater for non-potable uses.
• B. Indirect reuse adds treated water to groundwater or surface water before withdrawal; direct potable reuse injects treated wastewater directly into potable supplies.
• C. Indirect reuse is direct injection into distribution systems.
• D. Water reuse is only for industrial uses.

Answer: (B)

The main idea is that potable water reuse is distinguished by where the treated water goes before it becomes part of the drinking supply. In indirect potable reuse, the treated water is returned to the environment—into groundwater or a surface water body—and it is withdrawn later for treatment and distribution to consumers. In direct potable reuse, the treated water is placed directly into the potable water system, such as injecting it into the distribution system or into a raw water supply that feeds drinking-water treatment, with little or no environmental delay.

That’s why this statement is correct: it captures the critical difference between adding treated water to the environment first versus putting it straight into the drinking-water infrastructure. The other statements are off the mark because water reuse isn’t limited to non-potable uses, indirect reuse is not the same as direct injection into the distribution system, and reuse is not restricted to industrial applications.