The answer is NO. I have stayed in Thailand for a few years. And for more than 10 years prior to this, I have been travelling to Thailand, staying at various regions and places across Thailand. So regardless of whether you are in Bangkok, Phuket, Ko Samui, Chiang Mai or any other towns, do NOT drink directly from the pipe.
As far as I know and have been told, Thai people does not drink directly from the tap or piped water. They have advised us that the water from the tap is not safe for consumption even after it has been boiled if it has not been specially filtered.
The water from the tap is only used for washing and cleaning. Even when they do cooking, they would not use the water from the tap to make soups or gravy.
Why we cannot drink water from the tap in Thailand even though it has been boiled?
Reason is because it is ‘hard water’. I was told that the piping system in Thailand is still very old and there are minerals and rust deposits. And if you stay in a place long enough, you would know that shower tops and bidets would get clogged because of the hard water.
The shower head and bidet in my bathroom would get clogged up and water flow would be less smooth. I would need to scape off the blockages once every few months. Bathrooms would be covered in a layer of deposits which we would need to clean off with the most harsh detergent. Even that, sometimes these deposits could not come off and we have to manually scrape off with a steel spoon.
Where to obtain the source of drinking water?
If you are a tourist visiting Thailand, please buy your drinking water from any convenient stores like 7 Eleven. You can easily find 7 Eleven stores almost at any nook and cranny in Thailand. A 1.5 litres of drinking water typically cost between 13 to 18 baht depending on the brand.
For example, when we have friends over to visit and we charter a van to visit various places, we would buy large quantities of bottled water as we go along rest stops and convenient stores.
If you are staying in a longer period, you can buy 5 liters of water from 7 Eleven. After that, you can ask around if there are any self service water filtration stall in the area where you can fill up your plastic container with filtered water. When I stayed in my friend’s apartment in Bangkok, that was what we did. We have some 5 liters of water plastic containers which we reuse and fill up with filtered water that cost about 5 baht.
Then how does Thai people obtain long term drinking water?
I have stayed with a few friends from different region. Different households practice different ways. But one thing in common, no one take directly from the tap without any filtering.
1. Buy the water from a self service water filter station
I have mentioned that above where that is what some would do especially if they are staying alone without their family.
2. Order from the water supplier
I have a friend who would order water from a water supplier. The water comes in glass bottles which she would order by the crate. The bottled water would arrived with sealed caps. Once finished, we would replenish again (the glass bottles are being reused).
3. Filtered water system at home
Another friend of mine installed a filtration system in their home. There is a large filter outside, followed by another filter that connects to the tap just for drinking water. With that, then the water was safe to consume.
4. Clean water from the river
I have during one period stayed in the mountainous region of Mae Hong Son. The area is high up and the water flowing in the river is clean. We would cart the water from the river directly but would filter and boil it before drinking. This is only applicable if you are staying in an area still untouched by development.
5. Storage tanks to hold rain water or filtered water
You can sometimes see huge water storage tanks located outside houses. These tanks are sold by hardware and DIY outlets like DoHome, HomePro, Global House, Thai Watsadu, etc. They cost a few thousand baht and come in stainless steel and other durable materials.
I am staying in a plantation area in Thailand which is out of the city and metropolitan towns. Here, we would have huge water storage tanks like the above. During rainy season, we actually collect rain water, it is filtered into the tank. Sometimes just one afternoon of very heavy rain is enough to fill up most of the tank- we would collect only after we have cleaned the roof and it has been raining heavily for a few days (never collect on the first day after it had not rained for sometime). At the outside of the pipe of the tank, we would place a filtering cloth to filter off any dirt. The water would still be boiled before consumption.
After the tank of rain water finishes, we would wash the inside of the tank before refilling it.
Then during the dry weather, we would order filtered water where someone would come with a truck filled with huge containers of filtered water where it would be used to fill up the water storage tanks (we have a few in our place). It would cost us about 2000 baht for one huge tank but the water would last us for quite sometime.
One can really see the difference- the drinking water (either paid or rain water) does not leave hard deposits in the sinks or the water containers. But piped water would leave behind deposits which is hard to clean off.
Hope this information is helpful.