Erica Tze Ying WongChun Ket LeeYu Ting ChanZi Shan OoiNg Hien FuhWong Voon Son0000-0003-3209-7196Waye Hann KangOng Hooi Tin2026-10-192026-10-192025-10-0110.70387/001c.145236https://dspace-cris.utar.edu.my/handle/123456789/11785Reusable water bottles are popular nowadays due to the conveniences that they bring. Poor bacterial water quality in these bottles, however, can present risks to consumer health, as the drinking water can become a vehicle for waterborne illnesses. In this study, we aimed to investigate the bacterial water quality and its associated factors in the personal reusable bottles of medical students at our university. A survey, heterotrophic plate count (HPC), and coliform screening were used in this study. Among the 37 water samples, 46% were coliform-positive and 78% had a high HPC of >100 CFU/ml. These results are surprising considering that medical students should generally have a high level of health awareness. In addition, both bottleneck design and bottle material appeared to contribute to poor bacterial water quality, which should warrant further investigation. © 2025, National Environmental Health Association. All rights reserved.en-USbacterial water qualitycoliformsdrinking waterheterotrophic plate countreusable bottlesbacteriumrecyclingstudentwater qualityjournal-article