Can you drink tap water in Thailand?

No. Don’t drink tap water in Thailand.

The water leaving the treatment plant is fine. The problem is everything between the plant and your mouth: old pipes and rooftop storage tanks. Only about 10% of people in Bangkok drink straight from the tap, and if 90% of Bangkokians won't drink it, you shouldn't either. Drinking water is dirt cheap and on sale everywhere, so it's an easy rule to stick to.

Why the tap water isn't safe

Thailand isn't a country with dodgy treatment plants running on generators. Bangkok's water comes from the Chao Phraya and Mae Klong rivers and is treated by the Metropolitan Waterworks Authority (MWA) with sedimentation, filtration and chlorination. It meets WHO standards when it leaves the plant: the MWA tested 32,711 samples from 2,354 monitoring locations over five years (2011 to 2016) and hit 98.4% compliance.

The pipes are the problem. Bangkok was built fast, and parts of the network are 30 to 50 years old, laid in the 1970s and ’80s and still carrying water to millions of taps. Corroded joints add iron, manganese and in some cases lead (possibly from older solder connections), and sediment builds up. Rooftop tanks in older buildings sit baking in the tropical heat with whatever bacteria and algae decide to move in, and some haven't been cleaned since the building was built. E. coli has been found in samples collected at the tap, even when it wasn't present at the plant.

You'd get similar advice about old pipes in plenty of cities worldwide. Day to day, it just means don't drink from the tap, and the rest is easy to manage.

What about ice?

Stop worrying about ice. This is the single most common panic we see from first-time visitors. "Don't have ice in Thailand!" gets repeated in every nervous forum post, and it's mostly wrong.

Factory ice is made from purified, filtered water in hygienic facilities, and you can tell it by the shape: hollow cylinders with a hole through the centre, or uniform crescents. If you see those in your drink, it's factory ice and it's safe. Every restaurant, bar, cafe and 7-Eleven in any tourist area or city uses it, and Thais put ice in everything, including beer (seriously, iced beer is a thing here and honestly it makes sense when it’s 35 degrees out).

The only time you might think twice is at a very basic rural street stall using hand-chipped ice from big blocks. Even those blocks are usually made from filtered water at ice factories, so it's the handling and transport that varies, not the water. In practice, we’ve never had an issue, and we’ve been putting ice in our drinks across Thailand for years.

Brushing your teeth

Brushing your teeth with tap water is fine in Bangkok and all the major cities, because you're not swallowing any real amount. Plenty of long-term expats (us included) brush with tap water daily without any issues.

If you have a very sensitive stomach and you're still adjusting in your first few days, or you're somewhere rural where the tap water is visibly discoloured, use bottled water. Showering and washing your face are fine everywhere.

Cooking with tap water

Cooking with tap water is fine, because boiling kills bacteria and parasites. The MWA officially says Bangkok tap water is safe to drink, so it's certainly fine for rice, pasta and soup, and Thai households have been doing exactly that for decades. Most of them cook with tap water and drink filtered or bottled, which is a sensible approach whether you're here for two weeks or two years.

Boiling doesn't remove heavy metals or chemical contaminants, but that's a long-term accumulation issue, not something that'll affect you on a two-week holiday. If you live here and cook with tap water every day, a filter makes sense (see below).

Buying drinking water

Bottled water in Thailand is stupidly cheap, and you're never more than a few minutes from it.

7-Eleven and mini-marts - They're on every corner, sometimes two on the same block. A 600ml bottle is 7-10 baht (~$0.20-0.30 USD) and a 1.5-litre bottle 12-15 baht (~$0.35-0.45 USD). The main brands are Singha, Crystal (owned by ThaiBev), Chang and Namthip (owned by Coca-Cola). There's no real difference between them, so buy whatever's cheapest.

Restaurants and hotels - Restaurants and tourist areas charge 20-40 baht for the same bottles. Hotels are worse, at 40-80 baht from the minibar for water you could buy downstairs for 7 baht.

Refill stations - If you're staying anywhere longer than a few days, these are the move. The blue and white coin-operated machines sit outside apartments, near 7-Elevens and beside laundromats in any Thai neighbourhood. They use reverse osmosis plus UV purification and charge 1 baht per litre (sometimes 1 baht per 1.5 litres), so bring your own bottle or buy a reusable jug. Look for a recent service sticker, a clean nozzle and no rust. Most are well maintained, but skip the one that looks like it hasn't been serviced since 2019.

Delivery - Households get 5-gallon (18.9-litre) jugs delivered for 30-50 baht a jug, and most condos have a delivery service that comes through the building weekly.

If you're still planning your trip, our beginner tips for Thailand cover the rest of the basics.

If you live here

For those of us who live in Thailand full-time, the approach shifts from “buy bottles” to “set up a system.” Bottled water is cheap, but buying it every day gets old fast and makes a mountain of plastic.

Building water machines - Most condos and apartments in Bangkok and the bigger cities have an RO filtration machine in the common area, usually on the ground floor near the mailboxes. It's often free for residents or 1 baht per litre, and the quality depends on building management.

RO filters - An under-sink or countertop RO filter is the best option for long-term living. Installation runs 2,000-15,000 baht depending on the system, and Lazada and Shopee both carry the common brands: Mazuma, 3M, Mitsubishi Cleansui and Xiaomi. A decent Mazuma RO system costs around 8,000-15,000 baht and lasts years, with new filters (1,000-3,000 baht) every 6-12 months.

Delivery jugs - At 30-50 baht per 18.9-litre jug, they work out at about 1.5-2.5 baht per litre. That's more than a refill station, but it comes to your door.

Water is one of the cheapest line items when you're budgeting for life here, and our cost of living in Thailand breakdown shows how it fits in.

Water in different parts of Thailand

Water quality varies a lot depending on where you are.

Bangkok - Bangkok has the best water infrastructure in the country. The MWA serves Bangkok, Samut Prakan and Nonthaburi, and treatment quality is high, but the pipe and storage tank problems still apply, so don't drink it. Newer condos built after about 2010 tend to have better internal plumbing.

Chiang Mai - Chiang Mai is supplied by the Provincial Waterworks Authority (PWA), with decent treatment and the same pipe and tank risks as Bangkok. The water is harder up north, so calcium builds up in kettles faster. Not harmful, just annoying.

Phuket - Phuket is PWA-supplied and comparable to Bangkok. Same advice: stick to bottled or filtered.

The islands - Koh Samui, Koh Phangan, Koh Tao, Koh Lipe and the others generally have worse water infrastructure than the mainland, and some rely on desalination or water trucks in the dry season. Tap water quality is more variable, so definitely stick to bottled. Refill stations exist on the larger islands but are less common than on the mainland.

Rural Thailand - This is the most variable of all. Well water is common and quality varies hugely, and the PWA has identified only about 250 areas nationwide with confirmed safe tap water. Bottled water is on sale even in the smallest villages, so stick to it.

What if you do get sick?

Over 30 million tourists come to Thailand every year, and water-related illness is uncommon among the ones who drink bottled or filtered water. Most stomach problems that tourists blame on "the water" are actually caused by food handling: unwashed hands, or food sitting out at room temperature. People obsess over water while eating from the sketchiest stall they can find.

If you accidentally drink some tap water, probably nothing will happen. A sip or two won't send you to the hospital, and if you swallow some in the shower or while brushing your teeth, don't panic. The risk comes from drinking it regularly over time, or from particularly bad water in an old building with bad pipes.

If you do get a stomach bug, it's usually traveller's diarrhoea, which is unpleasant but not dangerous and passes in a few days. Pharmacies sell Imodium and oral rehydration salts over the counter for next to nothing. The more serious but rare risks from contaminated water are hepatitis A and giardia. Hepatitis A is preventable with a vaccine, so get it before you travel. It's one of the standard jabs recommended for Southeast Asia.

A hospital visit for a stomach bug is cheap here compared to back home, but with travel insurance for Thailand sorted before you arrive, you don't even have to think about it. If you're staying long-term, long-term health insurance is worth sorting out too. If you're reading up on health before your trip, our guide to avoiding bed bugs in Thailand is worth a look too.