Virological evaluation of domestic water purification devices commonly used in India emphasizes inadequate quality and need for virological standards.

OBJECTIVES To evaluate the performance of domestic water purification units with respect to contaminating enteric viruses. METHODS Eight domestic water purification systems widely used in India were evaluated using hepatitis E virus (HEV) as a model virus. For HEV concentration and detection, membrane filtration and real-time PCR were used respectively. Viral log reduction value (LRV) was calculated for each unit. RESULTS Viral log reduction value was 0.21 for unit 6 (polyester + carbon), 1.45 for unit 4 (filter + UV), 1.52 for unit 3 (filter + chlorine), 1.70 for a carbon + exhaust indication contact disinfection unit, 2.20 for an iodine resin unit, 2.51 for a dual filter unit and 6.53 for a hollow fibre membrane unit and a gravity-fed filter unit. Thus, only the technologies employed by the latter two were efficient in complete removal of HEV. CONCLUSIONS The majority of the water purifiers under use are inadequate. Virological standards in evaluating such devices need to be established urgently, in order to help manufacturers to improve the performance of such products and most importantly, to help consumers.