Chennai Study: RO Systems Fail Without Maintenance

Household reverse osmosis (RO) systems may not ensure safe drinking water if not properly maintained, according to a field study conducted in Chennai. Researchers found that microbial contamination, including E. coli, persisted in a significant percentage of post-RO water samples, indicating that regular maintenance and filter replacements are crucial. The study, published in the Journal of Exposure Science & Environmental Epidemiology, involved analyzing 262 water samples from 216 households.

Interestingly, the study observed a correlation between education levels and water safety. While RO systems reduced E. coli contamination from 71% in untreated water to 31% in treated water, higher educational attainment among respondents was associated with lower contamination rates. This underscores the importance of user knowledge and practices in maintaining water quality. Reliance on RO as a sole solution may also exacerbate inequalities, as lower-income households may struggle with ongoing maintenance costs.

A comprehensive approach involving reliable piped supply, regulation of point-of-use devices, and affordable servicing structures is advocated. Another study published in Scientific Reports in 2025 by Shohaib Mustafa et al. also highlighted that contaminated water is a leading cause of waterborne diseases and that domestic water filtration is a key countermeasure, with awareness and social influence being significant predictors of use, while cost remains a barrier.