Water Reuse

© photo iStockphoto / DenGuy

The truth is, the term “water reuse” is awkward nomenclature.  There is no other form of water usage other than water reuse. But the phrase does have meaning in an applied sense. Here we will explore different facets of water reuse as the term applies to engineered applications.

Let’s first start by categorization and definition.

There are few types of water reuse. Some of these categories overlap. Some nomenclature, such as “reclaimed water”, is used across different categories. Again, this nomenclature has meaning, but is rather arbitrary. All water is reclaimed, recycled, reused.


 Indirect Potable Reuse –  recovered wastewater that is treated to drinking water standards, and then is reintroduced to the potable water supply, often via groundwater recharge.

Direct Potable Reuse – wastewater that is recovered to drinking water standards and then reintroduced directly into the potable water supply, either directly into the distribution system, or into a stream or reservoir from which a utility draws its water.

Gray Water/Reclaimed Water- water which is treated to an acceptable level for applications such as irrigation, toilet flushing, and other beneficial but non-potable applications. Gray water and reclaimed water are different. A gray water system usually is completely client-side. Where a reclaimed water system is set up by a utility. Reclaimed water is distributed via purple pipe, which is a specification of the Uniform Plumbing Code, established by the International Association of Plumbing and Mechanical Contractors. Both gray water and reclaimed water may be distributed via purple pipe, however with different labels.

Stormwater Capture/Rainwater Harvesting –  capturing stormwater runoff for beneficial reuse. The level of treatment can range from minimal to elaborate, depending on the application.