Household water treatment and storage in the Western Province of Sri Lanka: an assessment of knowledge, behaviours, practices, and treatment effectiveness

ABSTRACT Centralized drinking water systems are the gold standard for safe water delivery. Yet household water treatment and safe storage (HWTS) provide an essential safeguard where centralized supplies are unreliable or absent. In Sri Lanka's Western Province – the country's most urbanized and industrialized region – bacteriological water quality remains variable despite high reliance on improved sources. This study surveyed 1,502 households in Colombo, Gampaha, and Kalutara and conducted paired microbial testing before and after household-level treatment. Six areas were examined: reported versus observed HWTS use, correct and consistent application, knowledge and behaviour, environmental health links, water quality outcomes, and other factors. Findings showed wide gaps between self-reported and actual use, particularly for boiling, and highlighted behavioural barriers such as the know-do gap, risk perception paradox, and low self-efficacy. When correctly applied, HWTS methods significantly improved drinking water quality. While HWTS can add to household burdens, it remains an important safeguard until all households achieve reliable access to safely managed, centrally treated water. Even then, its role during contamination events or service disruptions underscores the need for behaviourally informed, culturally grounded, and socially supported promotion strategies to sustain public awareness and effective use.