What is the best drinking water?

I would like to hear your experiences with drinking water. What type have you found to be safest, most thirst quenching and best tasting? I avoid tap because I rent an old home with nasty pipes. And I don't know if any of the filter pitchers, purifiers, etc. can overcome that? I don't have money to pay a lot. I drink plastic gallons of what is labeled as spring water. But it says reverse osmosis is used. Not sure what to make of that. Causes bitter and metallic taste in my mouth, plus upsets my stomach.