Water reuse offers a sustainable solution to meet growing water demands

The Department of the Interior Bureau of Reclamation awarded the Orange County Water District $437,544 in a Cooperative Agreement (CFDA 15.560, SECURE Water Act – Research Agreements) on December 4, 2025, to develop modernized microbial water quality monitoring methods for engineered water treatment and reuse systems. The award funds application of droplet digital PCR and whole-genome metagenomic sequencing techniques to measure removal of pepper mild mottle virus, adenovirus, and crass-like phage through advanced water treatment processes, improving characterization and detection of microbial communities to make these methods more accessible to water utilities. Performance occurs in Fountain Valley, California, with completion targeted for March 31, 2027. The program supports research and applied science that enhances the Bureau of Reclamation's ability to assess and respond to water quality conditions in the public interest.

Implementation requires diligent monitoring and rigorous regulatory frameworks to ensure robust treatment systems are designed and maintained for the protection of public health. While measurement of chemical water quality and operational parameters provides critical engineering controls to ensure production of high-quality water, they offer little direct biological water quality and pathogenic risk information. Traditional indicators such as e. Coli, male-specific coliphage, enterobacter, and total and fecal coliforms have historically been used as indicators for fecal contamination in conventional drinking water systems. Today, detection of e. Coli and fecal coliforms remain the best assay utilities have for targeted assessment of fecal contamination and biological risk. Modernized yet accessible methods for microbial water quality monitoring are needed for engineered water treatment systems to ensure safe and reliable production of potable water for reuse. The goal of this study is to leverage specificity of targeted microbial detection techniques offered by droplet digital PCR and couple this data with whole-genome metagenomic sequencing data to calculate removal of pepper mild mottle virus (pmmov), adenovirus (ADV), crass-like phage (crassphage) and improve the characterization, monitoring, and detection of microbial communities through advanced water treatment. Developing a modernized program will provide a path to make these advanced microbial methods more accessible to utilities and bring current microbial assessment programs into the 21ST century.