The tap water in Porto is safe to drink and of course can be used for cooking, bathing, etc and meets all EU regulations.
Porto’s water supply is very heavy in minerals and as chlorine is added at the treatment plant it can have a strong taste.
Most people in Oporto buy bottled water for drinking and use tap water for everything else.
The best way to avoid carrying plastic bottles of water is to install in your home a Reverse Osmosis Water Filtration System and very important, one with a mineral cartridge that adds minerals to the filtered water and balances the PH.
Let us explain… the reverse osmosis removes 99,9% of everything from the water, including minerals, by adding the mineral cartridge you get a perfect balanced healthy clean water, much better than most bottled waters.