Practical advice for Thailand
In short
You cannot drink tap water in Thailand. Filters and vending machines work well at first, but poor maintenance turns them into a risk — confirmed by research finding 28.5% of tested Bangkok machines contaminated. Bottled water is safe but expensive, full of microplastics, and hard on the environment. The smartest choice depends on how long you stay and what you will pay.
Bottles or checked vending machines
Buy known brands (Singha, Crystal, Nestlé Pure Life) or use a well-maintained vending machine. Always check the service label. Avoid machines without a service date or with cloudy/smelly water.
Rental filter or 19L delivery — best balance
A rental filter (Coway or local brands) with included maintenance removes neglect risk. Alternative: weekly 19L jugs from a trusted brand. Cheapest per litre: vending — only with proven maintenance.
Prefer owning an RO system? Set calendar reminders for filter changes (typically every 6–12 months). Neglect is worse than no filter.
Details that matter
- Restaurant ice: cylindrical ice with a hole = factory ice from filtered water (safer)
- Homemade or flat ice cubes = possibly unsafe
- Brushing teeth: relatively low risk in big cities; use filtered water if unsure
- Washing produce: use filtered or boiled water if eating raw
- Rooftop tanks: ask owners/managers to clean regularly — a forgotten contamination source
Source: JourneyBloom / AllAboutDrink Thailand 2025