RO systems should be properly maintained to be effective, the study says

The authors of the study argue that using only RO equipment as a stand-alone solution for municipal drinking water safety may not be effective. | Photo credit: File photo

A recent study found that installing reverse osmosis (RO) systems at home alone does not guarantee safe drinking water. Although the technology has been shown to be capable of removing microbes under ideal operating conditions, a field study in Chennai showed that microbial contamination was detected in samples from RO units, highlighting the lack of regular maintenance and filter replacement as key issues.

The results of the study “Evaluating Household Reverse Osmosis Systems for Microbial Safety: A Case Study from Chennai, India” were recently published in the peer-reviewed Journal of Exposure Science & Environmental Epidemiology. Researchers Suzan Kagan et al aimed to assess the microbial safety of drinking water before and after household RO treatment to understand how education and awareness affect household water and maintenance practices. A survey conducted in Chennai included 262 water samples from 216 households, examining both treated and source water to assess the effectiveness of household water treatment systems.

The authors wrote that while RO systems reduce contamination, 31% of post-RO samples still contained Escherichia coli (E. coli), compared to 71% in untreated water. Furthermore, level of education was found to affect the results: 36% of post-RO samples from postgraduate respondents contained E. coli compared to 83% among those with lower levels of education. They pointed out that RO systems reduce contamination but offer limited maintenance-free protection.

E. coli is a group of bacteria that normally lives in the intestines, but some strains can produce toxins that cause severe food poisoning, diarrhea and vomiting. Another article published in Scientific Reports in 2025 by Shohaib Mustafa et al on “Adopting Home Water Filtration to Combat Waterborne Diseases in Developing Countries” noted the fact that contaminated water was one of the main causes of several waterborne diseases such as typhoid, dysentery and salmonella, Salmonella liver infection. home water filtration was considered a way to counter the consumption of contaminated water from hazardous sources.

The study also suggested an interesting correlation that was observed between education level and the presence of E. coli in drinking water. Among respondents with a graduate degree, 36% reported the occurrence of E. coli contamination of their drinking water, while among respondents with no education, this figure increased to 83%. Many households assumed that once an RO machine was installed, no further vigilance was needed, leading to complacency with cleaning and maintenance and creating a gap between perceived and actual safety.

This highlights the critical role of user knowledge, practices and proper water handling in preventing contamination, especially in households using RO systems, according to the authors. Interestingly, the results of a 2025 study by Mustafa et al revealed that awareness of the risks associated with contaminated water, social influence, and knowledge about water pollution are the most significant predictors behind the use of home water filtration devices, while cost is a potential barrier.

In the Chennai study, the authors argue that using only RO equipment as a stand-alone solution to urban drinking water security may not be effective and may exacerbate inequities, as low- and middle-income households often purchase systems with great difficulty and then realize they cannot afford to maintain them. A chain of quality and hygienic water supply is required, starting with reliable piped supply, regulation of points of use, education on maintenance and hygiene, and affordable building services.

Published – 22 May 2026 08:05 IST