The water safety report based on quality measurements for Osasco can be found here.
Go to the page, click on 'Controle Semestre - Tables Resumo' and filter for the data for the Osasco municipality
According to the Numbeo water drinkability and accessibility index, tap water has a score of 75 / 100 (100 being best).
Numbeo considers this score to be "High"
1 adult could save about 402$ per year in Osasco by drinking tap water instead of buying bottled water.
๐ณ Drinking tap water would also help with reducing your plastic footprint and improve environmental pollution.
Like in most countries, water quality and accessibility differs from location to location, therefore it's the best to check the information available on that place.