As young qatari mentioned not only the rusty old pipes that could contaminate the water, but also the storage tanks that will have residue of dust, dirt and other contamination which the landlords keep a blind eyes to. Apart from that try boiling the tap water, you will notice Calcium deposits over time, what bottled company may usuaaly do is covert the tap water which is hard water and convert it to soft water using water softeners and then purify that water by removing chemicals used while softening and adding some minerals. I have no idea thogh which water is good for drinking hard water or soft water.
As young qatari mentioned not only the rusty old pipes that could contaminate the water, but also the storage tanks that will have residue of dust, dirt and other contamination which the landlords keep a blind eyes to. Apart from that try boiling the tap water, you will notice Calcium deposits over time, what bottled company may usuaaly do is covert the tap water which is hard water and convert it to soft water using water softeners and then purify that water by removing chemicals used while softening and adding some minerals. I have no idea thogh which water is good for drinking hard water or soft water.