Clean safe water from the sink is not something you'll find in most of the world, in fact. It's not just SEA.

https://en.wikipedia.org/wiki/File:Safe_drink_tap_water_map....

So basically it's only safe to drink tap water in western countries + Japan, Singapore, Chile, South Korea, and a few of the rich Arab countries.

I would argue that even the blue areas here would be speckled with lots of non-drinkable areas if you zoomed in, due to old lead piping and so on.

Any idea why that is? Why is safety of tap water high(I hope) priority in some parts of the world and not the others?

Is it simply the economics of water purification and delivery or something else?

The price of clean water is at least an order of magnitude less than the price of electricity, but the cost of creating a water grid is probably more expensive than the electricity grid.

You will notice that many of the countries with unsafe tap water also have electricity reliability problems. If the economics of electricity don't work, then the economics of safe water don't work at all.

It's expensive to control the quality of water from source all the way to tap. Just having visible clean running water is hard.

Bottled (mineral) water is a big business in Indonesia. Not sure if "people" are incentivized to change that anytime soon.

I don't think there's any conspiracy like this. It's just economic + (lack of) beauracracy. Installing and maintaining a functioning potable water supply across an entire country is expensive, but even harder is setting and maintaining standards.

I traveled often between Jakarta and Japan in 2018, 2019 and 2020. The real breath of fresh air for me was literally the fresh air back in Japan. After running around for a week through Jakarta, I would inevitably develop a deep cough and a clogged nose. That said, the people, the food, and as someone else pointed out the nightlife is amazing.

Somebody I know had asthma while she lived in Jakarta. It went away when she moved to Europe. I really liked Jakarta, but the air quality is one of the reasons why I won't go back again.