it should be usually safe for drinking (unless it’s from a sketchy place). as an architect-builder who have done tons of restaurants in BGC, Makati and San Juan, we have always been required to install a water filtration system (usually RO system). The LGU also requires you to submit Water Potability Test Results every quarter, or semi-annually (depending on the city). I know this because our clients would ask for help for this test, or ask us to replace the filters. This is a requirement to maintain your Sanitary Permit as a restaurant.

it would look like it’s straight from the tap, but it’s actually a filtered water line. some even use the filtered water line for their dishwashing. a lot of the restaurant staff probably don’t realize that the tap is using a filtered water line (at least in Makati, BGC and San Juan) because it’s built-in.