Thailand is not the Netherlands
Treated at the plant — risky on the way
Thailand scores 42.7 on the EPI for water quality (roughly 98th worldwide). Water is treated at the plant, but the problem is distribution: old, sometimes corroded pipes and rooftop tanks add bacteria, heavy metals and sediment. Even locals do not drink tap water straight from the tap.
Source: A Backpacker's World 2025 / JourneyBloom / AllAboutDrink
Home RO filters, vending machines, or large jugs
Most Thai households use one of three options: a home filter (increasingly RO), nearby coin-operated water machines, or weekly delivered 19-litre jugs. Buying small bottles is more a tourist/expat habit — costlier and more plastic.
Thailand’s water-filter market was worth USD 310 million in 2024 and grows about 10% a year — a clear sign that filtration is seen as necessary.
Source: Olympian Water Testing / JourneyBloom 2025
Quality varies a lot by location
In Bangkok the Metropolitan Waterworks Authority (MWA) reported in 2025 that treated water meets 21 parameters leaving the plant. By the time it reaches your tap — via old pipes and rooftop tanks — that guarantee is gone. In rural areas the picture is even less certain.
Source: MWA Consumer Confidence Report 2025 / AllAboutDrink