On the water front: in my opinion, the tap water in Brazil, at least in the big cities, is perfectly safe. Nonetheless, every middle class home here has a filtering system for three reasons: 1) the water is full of chlorine; 2) there is a small amount of silt in the water (brownish powdery sand); 3) in residential buildings, water is stored in large tanks on the roof and these tanks can become unsanitary if not cared for properly. The chlorine is obvious to the taste; the silt is completely below the level of perception. I myself drank the tap water for years before getting a filter.

On the visa front: the $100 fee is in reciprocation for what the US charges citizens of Brazil who apply for a US visa. However, the Brazilians will not put you through the tedious and humiliating application process the US imposes on Brazilian applicants. There have been rumors that Brazilian consulates in the US have received instructions to deny US applications in the same proportion that the US denies Brazilian applications, but this has not been confirmed. No visa is required for European Union citizens to enter Brazil because the EU does not require a visa for Brazilian citizens.