Drinking Water in Thailand: What's Safe and What Isn't

Thailand's tap water is treated and used for washing and cooking, but it is not safe to drink directly in most areas due to aging pipe infrastructure and potential contamination points between treatment and tap. Bottled water (น้ำดื่ม, nam duem) is available everywhere — a 1.5-litre bottle costs ฿7–15 at 7-Eleven or ฿3–6 from street market carts. Major brands (Singha Water, Crystal, Sprinkle) are all safe and reliably filtered. For environmental and cost reasons, an increasingly popular alternative is the water refill station (ตู้น้ำหยอดเหรียญ, blue vending machines on street corners) — these provide filtered drinking water for ฿1 per litre, and you refill your own bottle. Bring a reusable bottle specifically for this purpose. Most guesthouses and hotels provide complimentary bottled water or have filtered water dispensers in communal areas. Restaurant water: sit-down restaurants routinely serve complimentary water — this is typically filtered water that is safe. Ice in reputable restaurants and cafés is made from filtered water and safe; ice from street vendors serving cold drinks is generally also safe (made commercially). Ice that is not hollow cylinders or pre-formed shapes is sometimes made with tap water — exercise more caution with 'shaved ice' from street vendors, particularly in very local areas. Symptoms of waterborne illness (diarrhoea, stomach cramps) typically appear within 6–48 hours of exposure — oral rehydration salts from any pharmacy are the first response.