Evaluating household reverse osmosis systems for microbial safety: A case study from Chennai, India

A combined approach for studying water quality, attitudes, and practices is presented, focusing on urban low- and middle-income households in Chennai, India using reverse osmosis (RO) systems. Challenging the common assumption that in-home water treatment particularly RO fully resolves drinking water safety issues, this article presents one of the first empirical evaluations of the effectiveness of household-level filtration methods.

The study aims to assess the microbial safety of drinking water before and after household RO treatment and to understand how education and awareness influence household water and maintenance practices.

The study involved surveys, water sampling, and data analysis, conducted by a multi-disciplinary team from Tel Aviv University, IIT Madras, and local partners. Water samples were collected before and after RO treatment from 216 households (262 samples total), and socio-demographic information, including education levels and water-use behavior, was analyzed.

The findings revealed that while RO systems reduce contamination, 31% of post-RO samples still contained E. coli, compared to 71% in untreated water. Furthermore, education levels were found to influence outcomes: 36% of post-RO samples from postgraduate respondents contained E. coli, versus 83% among those with lower education levels.

Empirical evaluation of RO system effectiveness in urban Chennai households. 31% of post-RO household samples remained contaminated with E. coli. RO systems reduce contamination but offer limited protection without maintenance. Integrated survey and water testing reveal gaps in treatment efficacy perception. Post-RO contamination linked to respondent education level and user practices.