# Public health guidance on boiled water safety > Developing situation record from CLSTR: https://clstr.news/situations/public-health-guidance-on-boiled-water-safety > Updated: 2026-10-08T03:12:14.000Z. Sources: 3. Developments: 2. Health experts and organizations have provided guidance regarding the safety of consuming boiled water, specifically addressing concerns about overnight storage. While there are misconceptions that leaving boiled water out overnight creates dangerous levels of nitrites or carcinogens, health authorities clarify that such substances are typically inherent to the original water source rather than being produced by time. The World Health Organization (WHO) emphasizes that boiling effectively inactivates pathogens, but the primary risk is recontamination. Health Canada notes that boiling does not remove nitrates or nitrites and may increase their concentration through evaporation. To maintain safety, experts recommend storing boiled water in clean, sanitized containers with tight-fitting lids. Specific hygiene practices include avoiding the practice of topping up old water with new water in the same container, cleaning containers thoroughly rather than just rinsing them, and storing water in cool, dry places away from direct sunlight. ## Timeline ### 2026-10-08: Safety habits for consuming boiled water To maintain water safety, avoid keeping boiled water for extended periods, topping up old water with new, using unwashed containers, or storing water in hot, sunny locations. 2 sources. https://clstr.news/cluster/safety-habits-for-consuming-boiled-water ### 2026-09-24: Health advice on the safety of drinking boiled water left overnight Health experts clarify that boiled water left overnight does not automatically become toxic, emphasizing that safety depends on the initial water quality and preventing recontamination during storage. 3 sources. https://clstr.news/cluster/health-advice-on-the-safety-of-drinking-boiled-water-left-overnight --- Cite as: Public health guidance on boiled water safety. CLSTR, https://clstr.news/situations/public-health-guidance-on-boiled-water-safety