It's not obvious to me why ...

It's not obvious to me why these outlets require reverse osmosis treatment when they can use the piped water supply system of Barcelona that already provides drinking water to EU quality standards. Reverse osmosis is used to remove unwanted compounds from water, and may require much higher pressure than usually found in a municipal drinking water network, depending on the compounds it is desired to remove. Therefore each location could need an electricity power supply to power the reverse osmosis filtration. If the purpose of the reverse osmosis is to safeguard the health of users, then a much more serious issue is the design of the water delivery point - especially if these outlets are used by the general public and open to external contamination. Finally, water treated by reverse osmosis usually lacks non-harmful chemical constituents that make water taste good. Water utilities relying on reverse osmosis (for example to desalinate seawater) have to replace these compounds to restore hardness and make the water potable.