Drinking water and kiosks
In Rome there are many fountains with a good quality and fresh drinkable water.
And there are many kiosks selling water too.
If drinking water with gas is not a must for you... and if you want safe up to 2 Euros for half litre, you can use these fountains with no problem.
In particular, next to our support office (Fori Imperiali) there are a well used fountains in a garden with shadows area where eating ice creams looking the Coliseum