As bottled water is regulated by a different regulatory department than public water (tap water) systems, the regulatory compliance requirements vary greatly. Out of the 110 regulated chemicals, only 49 have the same maximum contaminant level (MCL) limits. The 61 remaining regulated chemicals have variances in maximum contaminant levels and in some instances, major disparities or no regulatory compliance requirements at all.
Suffice to say, your tap water is much safer to drink than bottled water providers. The regulatory requirement comparables (click here) speak for themselves.