What Is Potable Reuse? A Plain-English Guide to Drinking Recycled Water

As droughts deepen and traditional supplies shrink, more U.S. cities are turning to a once-taboo idea: purifying wastewater back into drinking water. Here is how it actually works.

Two flavors: direct and indirect

Indirect potable reuse (IPR) blends purified water into an environmental buffer — a reservoir or aquifer — before it is withdrawn and treated again. Direct potable reuse (DPR) sends purified water back into the drinking-water system without that buffer, which is more efficient but requires the highest level of treatment and monitoring.

The treatment train

A typical advanced purification process uses multiple barriers: microfiltration to remove particles, reverse osmosis to strip out salts and most contaminants, and ultraviolet light with advanced oxidation to break down anything that remains. The result meets or exceeds federal drinking-water standards.

The 'yuck factor'

The biggest obstacle is often psychological, not technical. Utilities address it with demonstration facilities, public tours, transparent water-quality data, and education — the same approach St. George, Utah and dozens of other communities are now taking.