# What is the Difference between Conventional Drinking Water, Potable Reuse Water, and Nonpotable Reuse Water? A Microbiome Perspective

## TL;DR

This study uses microbiome analysis to distinguish between potable and nonpotable water types, showing how microbial signatures can help assess water quality and treatment effectiveness.

## Contribution

The study introduces microbial community profiling as a novel method for high-resolution water quality assessment based on microbiome composition.

## Key findings

- Microbiome composition clearly differs between potable and nonpotable water types across U.S. water systems.
- Specific taxa like Desulfobacterota, Patescibacteria, and Aeromonas effectively discriminate between potable and nonpotable waters.
- Core/abundant taxa in nonpotable waters include Myxococcota and NS11.12_marine_group, with exceptions like Ralstonia in potable waters.

## Abstract

As water reuse applications expand, there is a need for
more comprehensive
means to assess water quality. Microbiome analysis could provide the
ability to supplement fecal indicators and pathogen profiling toward
defining a “healthy” drinking water microbiota while
also providing insight into the impact of treatment and distribution.
Here, we utilized 16S rRNA gene amplicon sequencing to identify signature
features in the composition of microbiota across a wide spectrum of
water types (potable conventional, potable reuse, and nonpotable reuse).
A clear distinction was found in the composition of microbiota as
a function of intended water use (e.g., potable vs nonpotable) across
a very broad range of U.S. water systems at both the point of compliance
(Betadisper p > 0.01; ANOSIM p <
0.01, r-stat = 0.71) and point of use (Betadisper p > 0.01; ANOSIM p < 0.01, r-stat = 0.41). Core and discriminatory analysis further
served in
identifying distinct differences between potable and nonpotable water
microbiomes. Taxa were identified at both the phylum (Desulfobacterota,
Patescibacteria, and Myxococcota) and genus (Aeromonas and NS11.12_marine_group) levels that effectively
discriminated between potable and nonpotable waters, with the most
discriminatory taxa being core/abundant in nonpotable waters (with
few exceptions, such as Ralstonia being
abundant in potable conventional waters). The approach and findings
open the door to the possibility of microbial community signature
profiling as a water quality monitoring approach for assessing efficacy
of treatments and suitability of water for intended use/reuse application.

This study demonstrates the potential
for profiling microbial
community composition via 16S rRNA gene amplicon sequencing as a high-resolution
tool for classifying water quality and its corresponding suitability
for various water use and reuse applications.