Most of the US does too.

And of those that don't it's mostly because their water is supplied by a well in an area where the groundwater has minerals that affect smell/taste and it's cheaper to buy bottled than to filter them.

I think the USA is the only 1st world country with legitimate problems in the potable tap water department.

Well, them and Canadian Indigenous reserves lol. But those have been described as 3rd world anyways.