It seems like a silly question for most of my travels, as I 'll be in a hotel, but I will travel a little bit.
It depends on who you ask, basically.
The latest report I can find states that it's "safe to drink - for now".
The water quality is managed by The Manila Water Company, and they do monthly checks of over 1000 samples.
However, it's also worth noting the article points out that during rainy season, the risk of contamination is higher from pipes being submerged in floodwaters.
However, that's the "official" report. The article goes on to say: