I'll be traveling to Taiwan in Jan next year when my lo turns 15mo. Is it necessary to bring tap water to mix with water over there for his consumption?

For me, I will buy bottled distilled water and boil it in the hotel room for my little ones.

You need not bring tap water. Just buy mineral water from local 7-11 and boil it.

I will buy a mineral water and boil it .. Will be better

Buying bottled water is more convenient