Drinking water, and the blue twenty-litre bottle

Nobody in Vietnam drinks water from the tap, including the people who live here. That is not a warning aimed at visitors; it is how the country is plumbed, and there is a whole domestic system built around it.

Once you see the blue bottles going past on the back of a bike, the rule stops feeling like a precaution and starts looking like infrastructure.

What do households actually drink?

Purified water in a returnable bottle, delivered. The binh nuoc is a twenty-litre blue container on a dispenser in the corner of most homes, offices and shops. A man on a bike brings a new one when you call.

At about 26,000 dong to the dollar, the twenty-litre bottle is under three dollars, which is why nobody boils anything they do not have to.

So how careful does a visitor need to be?

Less than the internet suggests, in three of four cases. Drink bottled or boiled, and the question resolves itself: hotels leave bottles in the room, restaurants pour from bottles, and tea is boiled by definition.

The two edges are teeth and ice. Brushing with tap water is what most residents do and what most travel clinics advise against. Bottled water costs pennies here, so take the cautious side and stop thinking about it. Ice is more nuanced, and the street food safety guide has the actual evidence.

Where does the rule really bite?

Raw things rinsed in tap water rather than the water itself. A plate of herbs, cut fruit from a cart, a salad — all washed in whatever the stall has, none of it sterilised by the rinse.

Rinsing is the mechanism behind most traveller stomach upsets here, and it has nothing to do with drinking. The herbs guide explains what arrives raw on the table and the health guide covers what to do when something does go wrong.

What about the plastic?

Plastic is the honest problem with all of this. A two-week trip on half-litre bottles is thirty pieces of plastic a person, in a country whose waste system is visibly overloaded.

Two things help. A filter bottle handles tap water anywhere and pays for itself on a long trip. Refill points also exist in the tourist towns: hostels, cafes and dive shops in Hoi An, Da Nang and on the islands, often free and sometimes a few thousand dong.

Is the tap water dangerous, exactly?

Not dramatically. The utility treats the supply and the last stretch undoes it: old pipes, rooftop tanks and intermittent pressure. That is a different problem from a contaminated source.

Showering, washing and cooking with it are entirely normal. Nobody boils bathwater, and no restaurant rinses vegetables in bottled water. The line is drinking, and it is a plumbing line rather than a hygiene one.

How do you order water without over-buying?

Ask for nuoc suoi, which is bottled still water, and expect a 500 ml bottle for 5,000 to 10,000 dong. Restaurants bring a bottle per person unless you say otherwise; a large one on the table costs less and refills everybody.

Mini-marts sell multipacks at the lowest price per litre in the country, and a hotel fridge charges several times that for the same bottle. The convenience store guide covers which chains stock what.

What should you actually order in the heat?

Tra da, like everybody else. Iced green tea arrives free with meals at most street places, costs a few thousand dong on its own, and has been boiled before it was chilled.

After that, the smoothies and juices guide covers sinh to and sugarcane, and the coffee shops guide covers the other thing served over a mountain of ice. Water is the least interesting drink available here, which is part of why the question resolves so easily.