Generally all the packaged bottles(Bislery) will have tds near to 30. Whereas the packaged cans(20 ltrs) will have a tds of 100-200. Which is aso good to drink.
If your available water(bore or well) water tds is much higer that is greater than 500tds then you can go for RO system. RO has two membranes, one reduces 50% of tds and other reduces 90% of tds.
If the tds of your water is < 200 then better to take UV system purifier. Which will give the output water with same tds by killing bacteria.