Is tap water safe to drink in Hanoi?
No. Do not drink Hanoi tap water. The municipal supply is treated but aging pipes introduce contaminants between the treatment plant and your tap. Buy bottled water (5,000–10,000 VND for 500ml at convenience stores, 20,000–30,000 at hotels). Ice at restaurants is factory-made and safe. Brushing teeth with tap water is fine for most people — just don't swallow.
The water coming out of Hanoi taps is treated at the municipal level. The problem is what happens between the treatment plant and your glass — aging pipes, intermittent pressure, and storage tanks in older buildings introduce contaminants that make the water unsafe to drink straight.
What to do instead
Buy bottled water. A 500ml bottle costs 5,000 VND at convenience stores (Circle K, WinMart, FamilyMart — all over the Old Quarter). A 1.5L bottle is 10,000–12,000 VND. Hotels typically provide two complimentary 500ml bottles daily. If you’re staying more than a few days, buy a 5L jug for 20,000 VND and refill your day bottle.
Filtered water stations exist at some cafés and coworking spaces. The water is fine — these are commercially maintained.
Ice is safe (with one check)
Ice at restaurants, cafés, and beer corners in central Hanoi is factory-made from filtered water. It arrives as cylindrical tubes with a hole in the center. If you see that shape in your glass, the ice is safe.
The ice to avoid is block ice — large cubes chipped from a solid block by hand. This type is made from unfiltered water and appears at very small street stalls outside the city center. In practice, you’ll almost never encounter it in Hoàn Kiếm or Ba Đình districts.
Brushing teeth
Tap water is fine for brushing teeth — the amount you’d accidentally swallow is negligible. If you have a particularly sensitive stomach or are immunocompromised, use bottled water. Most visitors don’t bother and have no issues.